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Showing papers in "Plant Breeding in 1995"


Journal ArticleDOI
TL;DR: Out of 25 genotypes tested, five were identified with no significant difference in head blight scores, but differing significantly in yield after artificial inoculation, i.e. tolerance differences were detected at different resistance levels.
Abstract: Resistance of wheat to Fusarium head blight caused by Fusarium graminearum and F. culmorum was identified in natural epidemics in 1985 and 1987 as well after artificial inoculations (1983–1988 and 1984–1987). Out of 25 genotypes tested, five were identified with no significant difference in head blight scores, but differing significantly in yield after artificial inoculation, i.e. tolerance differences were detected at different resistance levels. Some genotypes that were similar in yield or head blight scores differed in seed infection severity. Genotypes with awns were more susceptible to head blight when tested under natural epidemic condition in the field; but this trait did not influence head blight severity in artificial inoculations. Dwarf genotypes were more severely infected by head blight than tall genotypes under natural conditions, but genotypes of different plant height classes were similarly susceptible after artificial inoculations. In the early generations of a breeding programme resistance measured by visual evaluation of artificial inoculation is the most important way to screen. If selection of dwarf and awned genotypes cannot be avoided, the higher susceptibility caused by awns and dwarfness under natural epidemic conditions can be decreased by a higher level of physiological resistance, as variability in physiological resistance is available. In later generations, traits like percentage of seed infection or tolerance can be identified by additionally measuring yield reduction. Stability of disease reaction appears to be connected with resistance level, the most resistant genotypes are the most stable, and the most susceptible ones tend to have more unstable reactions in different epidemic conditions.

720 citations


Journal ArticleDOI
TL;DR: Two field experiments were carried out with seven wheat cultivars representing different eras of plant breeding, to evaluate genetic improvement over the last century in grain yield, height, biomass, harvest index and grain yield components, indicating that during recent years harvest index has been kept as the main attribute responsible for increases ingrain yield.
Abstract: Two field experiments were carried out with seven wheat cultivars (three of them, including a commercial hybrid, released during the last 10 years) representing different eras of plant breeding, to evaluate genetic improvement over the last century in grain yield, height, biomass, harvest index and grain yield components. Plots were fertilized and irrigated, and lodging and diseases were prevented. Main culm height was negatively correlated with the year of release of the cultivars, probably as a consequence of selection for increased lodging resistance. There was no significant association between total above-ground biomass and year of release of the cultivars. On the other hand, grain yield increased as newer cultivars were released. Results indicate that during recent years harvest index has been kept as the main attribute responsible for increases in grain yield. In general, number of grains/m2 was associated with increases in grain yield during the century. However, the newest cultivars showed an increased grain weight. In both growing seasons, cultivars released before 1980 showed a trend towards reduced grain weight, but cultivars released after 1987 had a similar number of grains per m2 with a higher grain weight than their predecessors. This was probably because the most modern cultivars have a longer grain-filling duration with a similar length of growth cycle.

221 citations


Journal ArticleDOI
TL;DR: The objective was to test whether the action of Rht1 and Rht2 alleles in improving grain yield depended upon sowing date, and as expected, the dwarfing genes significantly reduced plant height in both sowings and growing seasons.
Abstract: Grain yield and some of its physiological determinants were analysed in a field study conducted over two growing seasons with standard-height (SH), semi-dwarf(SD) and dwarf (DD) isogenic lines ofa spring wheat sown at recommended and delayed dates. The objective was to test whether the action of Rht1 and Rht2 alleles in improving grain yield depended upon sowing date. As expected, the dwarfing genes significantly reduced plant height in both sowings and growing seasons. There was a tendency for the SD line to produce more biomass than the SH and DD lines, although the differences were mostly not significant. Harvest index was linearly and negatively related to plant height. Consequently, the SD and SH line showed the highest and lowest grain yields in all environments. The optimum height for grain yield was estimated to be c. 70 cm, and this value was not affected by sowing date. Lines carrying Rhtl and/or Rht2 alleles always showed more grains/m 2 (owing to an increased number of grains per spike and spikes/m 2 ) than the SH line. Conversely, average grain weight was negatively associated with the number of grains/m 2 . Because the slope of this negative relationship was smaller (less negative) than that representing complete compensation, the relationship between grain yield and number of grains/m 2 was hyperbolic. Although these relationships are frequently regarded as a reflection of increased competition among grains when the number of grains/m 2 is increased owing to the use of semi-dwarf genes, two alternative hypotheses are analysed and discussed.

139 citations


Journal ArticleDOI
TL;DR: Comparisons involving 28 random F 2 -derived F 6 wheat lines from the cross suggested that advanced derivatives with the 1BL/1RS chromosome translocation possess superior agronomic performance in both full and reduced irrigation conditions when compared with 1B derivatives.
Abstract: Comparisons involving 28 random F 2 -derived F 6 wheat (Triticum aestirum L.) lines from the cross, 'Nacozari'/'Seri 82', suggested that advanced derivatives with the 1BL/1RS chromosome translocation possess superior agronomic performance in both full and reduced irrigation conditions when compared with 1B derivatives. This performance advantage was attributed to high grain yield, above-ground biomass at maturity, grains/spike, 1000-grain weight and test weight. The 1BL/1RS lines were shorter with delayed flowering and maturity. The superiority of the 1BL/1RS translocation group on grains/m 2 was expressed only under the full irrigation environment. Higher harvest index, longer spike-length and grain-filling period were detected only under reduced irrigation conditions. A significant grain yield relationship with test weight was detected only among the 1BL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1B genotypes.

111 citations


Journal ArticleDOI
TL;DR: Results indicated that bees were the most likely agent for long-distance pollen dispersal and the effectiveness of 200- and 400-m isolation distances were evaluated for small-scale trials of oilseed rape.
Abstract: The effectiveness of 200- and 400-m isolation distances were evaluated for small-scale trials of oilseed rape (Brassica napus L.). These distances have been used for previous transgenic release experiments and are commonly adopted for production of basic and certified breeders seed. A 400-m 2 donor plot contained plants with a dominant transgene conferring resistance to the herbicide glufosinate-ammonium. This character was used as a selectable marker to measure the frequency of hybrid formation in 400-m 2 target plots of non-transgenic rape. Seeds produced by the non-transgenic plants were permitted to fall onto the plots and allowed to germinate. At the first true-leaf stage, the plants were sprayed with glufosinate-ammonium. Surviving plants were resprayed, and a subsample assayed for the presence of the transgene using a colorimetric assay and Southern-blot analysis. The average frequency of hybridization over two replicates was 0.0156% at 200 m and 0.0038% at 400 m. These estimates are within the limits established for the production of basic seed (0.1%). Results indicated that bees were the most likely agent for long-distance pollen dispersal.

102 citations


Journal ArticleDOI
TL;DR: Hydroponic screening of wheat seedlings for Al tolerance may be used in breeding programmes or in screening germplasm collections after evidence that this short duration and simple screening technique provides a highly significant correlation with previous acid-soil Al-tolerance evaluations was presented.
Abstract: The objective of this study was to correlate root length of wheat (Triticum aestivum L.) genotypes grown in Al-containing, acidic hydroponic solutions, with root weights from acid-soil experiments and field scores from Brazilian acid-field trials. A total of 43 wheat genotypes, primarily from Brazil, were evaluated by growing seedlings for 4 days in hydroponic solutions containing 0.0–4.0 mg/l Al. The root growth rate of all the genotypes was reduced with the addition of Al to the solution and the Al-sensitive and Al-tolerant wheat genotypes were clearly identified. Genotypes with intermediate Al-tolerance levels showed variable root lengths in response to Al stress. Correlations between root length or a root tolerance index (RTI) in the Al solutions versus acid-soil experiments and acid-field trials were highly significant (r = 0.71–0.85, P < 0.01). The most significant correlation was observed among seedlings grown in 1 mg/1 Al. This study presents evidence that this short duration and simple screening technique provides a highly significant correlation with previous acid-soil Al-tolerance evaluations. Furthermore, the data obtained suggest that hydroponic screening of wheat seedlings for Al tolerance may be used in breeding programmes or in screening germplasm collections.

83 citations


Journal ArticleDOI
TL;DR: In comparative investigations, F 1 hybrids, produced from crosses between poor/non-responsive and responsive genotypes, showed a fair level of response, even the case of a poor response in donor parent, and the ploidy level of the resulting plants was determined by flow-cytometric analysis.
Abstract: An in vitro anther-culture method has been improved by using young mother plants and by using frequent subcultures, thus increasing the androgenic yield in different Capsicum annuum L. genotypes. An assortment of peppers was used, composed of 15 genotypes (four breeding lines, seven cultivars and four F 1 hybrids). A new system for qualifying the androgenic response was established. For use in practical breeding. a minimum of 5 % of plant regeneration was proposed as the criterion for a fair response. Accordingly, one excellent, one good and eight fair responses were identified among the genotypes investigated. As compared to the standard cultivar, 2 genotypes gave a significantly better response, i.e. Feherozon' (75.8%) and 'Szechuan 90716' (21.0%). In comparative investigations, F 1 hybrids, produced from crosses between poor/non-responsive and responsive genotypes, showed a fair level of response, even the case of a poor response in donor parent. The ploidy level of the resulting plants was determined by flow-cytometric analysis.

80 citations


Journal ArticleDOI
TL;DR: This investigation focuses on the identification of random amplified polymorphic DNA (RAPD) markers linked to the Pl 1 gene for mildew resistance, which has introgressed from Malus robusta into cultivated apples.
Abstract: The availability of molecular markers linked to mildew resistance genes would enhance the efficiency of apple-breeding programmes. This investigation focuses on the identification of random amplified polymorphic DNA (RAPD) markers linked to the Pl 1 gene for mildew resistance, which has introgressed from Malus robusta into cultivated apples. The RAPD marker technique was combined with a modified 'bulked segregant analysis' mapping strategy. About 850 random decamer primers used as single primers or in combinations were tested by PCR analysis on the basis of resistant and susceptible DNA pools. Selected primers producing RAPD fragments were applied in an additional selection step to M. robusta and genotypes representing intermediate breeding stages of the breeding population 93/9, for which a 1:1 segregation could be observed for the resistance trait. Seven RAPD markers, all representing introgressed DNA sequences from M. robusta, were identified and arranged with the Pl 1 locus in a common linkage group. The two most tightly-linked RAPD markers, OPAT20 450 and OPD2 1000 were mapped with a genetic distance of 4.5 and 5 cM, respectively, from the Pl 1 gene. Both markers are suitable for marker-assisted selection in apple breeding. The polymorphic DNA fragment OPAT20 450 was cloned and sequenced, and longer primers for the generation of a sequence-characterized amplified region (SCAR) marker have been constructed; this marker was easier to score than the original RAPD marker.

66 citations


Journal ArticleDOI
TL;DR: Correlations between the results of the SDSS test and the mixograph were highly significant, but no correlation was found between these results and protein and vitreousness contents.
Abstract: The objective of this paper was to study the differences between some prolamin variants coded at the loci Glu-3/Gli-1, Glu-1 and Gli-A2 and their relative roles in durum-wheat quality. F 3 lines from four durum wheat crosses ('Abadia' x 'Mexicali', 'Oscar' x 'Ardente', 'Oscar x Mexicali' and 'Alaga' x 'C. of Balazote') were analysed for gliadin and glutenin composition by electrophoresis. Whole-grain-derived samples were analysed for SDS sedimentation (SDSS) value, mixing properties, and contents of protein and vitreousness. The glutenin patterns LMW-2, LMW-2 - and LMW-2 (CB) at Glu-B3/Gli-B1 were associated with better gluten quality than were LMW-I and LMW-2 * . The glutenin subunits LMW4 and LMW3 + 15 at Glu-A3/Gli-Al and HMW1 showed better mixing properties than LMW7 + 12, LMW5 and the null phenotype, respectively. The HMW glutenin subunits 20 + 8 at Glu-Bl showed a negative association with gluten quality, but the rest of the HMW glutenin subunits and α-gliadins did not show any influence on gluten quality. Correlations between the results of the SDSS test and the mixograph were highly significant, but no correlation was found between these results and protein and vitreousness contents. The results are discussed in relation to the development of durum wheat varieties with improved qualities.

64 citations


Journal ArticleDOI
TL;DR: Studies of F 2 and F 3 populations from crosses with the susceptible 'Avocet' indicated that intermediate levels of adult plant stripe rust resistance in cultivars 'Harrier', 'Flinders' and 'M2435' were inherited monogenically, whereas King possessed two genes for resistance.
Abstract: Long-term resistance to rust diseases depends on the identification and use of durable resistance sources or on the continuing use of new resistances and combinations of genes for specific resistance. These studies include four Australian wheats with intermediate, but inadequate levels of resistance and a French wheat 'Hybride-de-Bersee' ('Bersee'), with reputed durable resistance to stripe rust. Studies of F 2 and F 3 populations from crosses with the susceptible 'Avocet' indicated that intermediate levels of adult plant stripe rust resistance in cultivars 'Harrier', 'Flinders' and 'M2435' were inherited monogenically, whereas King possessed two genes for resistance. Cultivars Harrier and M2435 possessed the same gene. Similarly, cvs. King and Flinders carried a gene in common. Like 'Harrier' and 'M2435', 'King' and 'Flinders' share common parents. The higher level of resistance in 'Bersee' was controlled by four genes. This conclusion was based on conventional genetic analysis, tests on F 2 -derived F 7 single-seed descent lines and testcross progenies.

56 citations


Journal ArticleDOI
TL;DR: Among the cytoplasmic-nuclear male sterility (CMS) systems reported in pearl millet, Pennisetum glaucum (L.) R. Br., the Am=A4 system produces the highest frequency of male-sterile hybrids as mentioned in this paper.
Abstract: Among the cytoplasmic-nuclear male sterility (CMS) systems reported in pearl millet, Pennisetum glaucum (L.) R. Br., the Am= A4 system produces the highest frequency of male-sterile hybrids. A CMS source identified in a large-seeded gene pool (LSGP) was compared with the A4 system. Seven diverse restorer lines of the A4 system produced hybrids with 81A4 that were all fertile (pollen-shedding score 4 and 68–89% selfed seedset). In contrast, all the hybrids of these inbreds made with the isonuclear line with the LSGP cytoplasm were sterile (pollen-shedding score 1 and 0–3% selfed seedset). Topcross hybrids of four diverse composites made with 81A4 had 10–35% plants that had good fertility (> 50% selfed seedset). In comparison, no plant of any topcross hybrid with the isonuclear line having LSGP cytoplasm exceeded 20% selfed seedset, and it was rare for a plant to exceed even 10% selfed seedset. These differential fertility restoration patterns of hybrids indicate that the LSGP cytoplasm represents a CMS system that is different from the A4 and, by implication, from all those reported to date. This new CMS system is designated A5

Journal ArticleDOI
TL;DR: Gel-electrophoretic analyses detected polymorphism of two waxy (Wx) proteins, Wx-Al andWx-Bl, in 334 accessions of the emmer group of tetraploid wheat, Triticum dicoccoides, T. dicoccum and T. durum.
Abstract: Gel-electrophoretic analyses detected polymorphism of two waxy (Wx) proteins, Wx-Al and Wx-Bl, in 334 accessions of the emmer group of tetraploid wheat, Triticum dicoccoides, T. dicoccum and T. durum. The null allele for the Wx-Al protein (Wx-Alb) was found in one accession of T. dicoccoides and seven of T. dicoccum, but it was not present in those T. durum accessions analysed. The null allele for the Wx-Bl protein (Wx-Blb) did not occur in three emmer-wheat species. Wx-Al and Wx-Bl proteins showing alteration in mobility in SDS-PAGE gel or in isoelectric points were found in five accessions and considered to be the products of new alleles, Wx-Ald, Wx-Ale and/or Wx-Bld. Densitometric analysis of Wx protein bands revealed that Wx-Al was present in smaller amounts than Wx-B1 in almost all accessions.

Journal ArticleDOI
TL;DR: Male-sterile plants closely resembled the normal fertile B. juncea in general morphology, but had delayed flowering when compared with fertile 'Pusa Bold' which flowered in 45 days.
Abstract: A cytoplasmic male-sterile (CMS) line of Brassica juncea has been developed by combining the cytoplasm originating from the somatic hybrid Trachystoma ballii + B. juncea, and the nucleus of B. juncea cv. Pusa Bold by repeated backcrossing. Male-sterile plants closely resembled the normal fertile B. juncea in general morphology, but had delayed flowering (5-7 days) when compared with fertile 'Pusa Bold' which flowered in 45 days. Stamens of the male-sterile line were transformed into petaloid structures. Pollen abortion occurred after tetrad formation. Female fertility of the male-sterile line was normal. Molecular analysis of organelle genomes indicated extensive mitochondrial DNA recombinations in the CMS line. Preliminary analysis of the chloroplast genome of the CMS line also indicated chloroplast DNA recombination.

Journal ArticleDOI
TL;DR: The utility of doubled haploid populations for determining the genetics of multiple disease resistance in barley shows the utility of an anther-culture-derived doubled-haploid population produced from F 1 plants from a cross of this accession and the susceptible breeding line SM89010.
Abstract: The barley accession Q21861 possesses resistance to the stem-rust (Puccinia graminis f.sp. tritici), leaf-rust (P. hordei), and powdery-mildew (Blumeria graminis f.sp. horder) pathogens. An anther-culture-derived doubled-haploid population was produced from F 1 plants from a cross of this accession and the susceptible breeding line SM89010 as a means of rapidly and efficiently determining the genetics of multiple disease resistance. The doubled-haploid population segregated 1 :1 (resistant : susceptible) for resistance to the stem rust pathotype QCC indicating the involvement ofa single resistance gene, rpg4. Two-gene (3 :1) and one-gene (1 :1) segregation ratios were observed for resistance to the stem-rust pathotype MCC at low (23-25°C) and high (27-29 ° C) temperature, respectively. These different segregation patterns were due to a pathotype x temperature interaction exhibited by rpg4 and Rpgl, another stem-rust-resistance gene present in Q21861. One-gene and two-gene segregation ratios were observed in reaction to the leaf rust and powdery mildew pathogens. These data demonstrate the utility of doubled haploid populations for determining the genetics of multiple disease resistance in barley.

Journal ArticleDOI
TL;DR: Allelism to the highly polymorphic Mia locus was demonstrated for the powdery-mildew resistance of two Hordeum spontaneum derived winter–barley lines by testing the F2 progeny of crosses between these lines and the winter-barley cv.
Abstract: Allelism to the highly polymorphic Mia locus was demonstrated for the powdery-mildew resistance of two Hordeum spontaneum derived winter–barley lines, ‘110-4 × Sonja’ and ‘142–29 × Dura’, by testing the F2 progeny of crosses between these lines and the winter-barley cv. ‘Triton’ (Mlal3) with two appropriate isolates. The results were confirmed by RFLP analysis, using the probe MWG 1H036, which is very closely linked to the Mia locus. The designations Mla29 and Mla32 are proposed for the genes identified in the two lines.

Journal ArticleDOI
TL;DR: Efforts in future breeding should concentrate on the improvement of health and the development of genotypes suitable for cultivation in suboptimal climates and regions, as well as for special applications.
Abstract: Carrot breeding in the past 150 years has resulted in varieties with high yield, a short growing period, and excellent root colour. Recently, hybrid varieties have demonstrated good uniformity of roots, a quality accepted by most consumers. By contrast, only a few resistant varieties (mainly open-pollinated varieties) are offered by seed companies, most being resistant to Alternaria. Hybrid breeding offers a chance of combining good uniformity and different sources of resistance. Efforts in future breeding should concentrate on the improvement of health and the development of genotypes suitable for cultivation in suboptimal climates and regions, as well as for special applications.

Journal ArticleDOI
TL;DR: Fatty-acid composition and fat content showed remarkable variation, and DH-lines exceeded cross parents in some cases for both fat content and linolenic-acid proportion, indicating that anther culture is a useful tool in linseed breeding.
Abstract: In the course of a breeding programme for high-linolenic-acid linseed (oilflax, Linum usitatissimum L.) doubled-haploid lines (DH-lines) of three F1 hybrids were generated using an anther-culture technique. A total of 82 DH-lines were generated and multiplied in 1993, of which 39 were suitable for testing in a repeated field trial in 1994. Yield, fat content and fatty-acid composition were determined. The yield of the DH-lines was not significantly different from that of respective mid-parent values. Fatty-acid composition and fat content showed remarkable variation, and DH-lines exceeded cross parents in some cases for both fat content and linolenic-acid proportion. Superior DH-lines surpassed mid-parent linolenic-acid-content values by 4.5% and fat content by 1.9%. The results indicate that anther culture is a useful tool in linseed breeding.

Journal ArticleDOI
TL;DR: A new procedure is described for rapid and efficient plant regeneration from leaf explants of Cucumis sativus and C. anguria, where young leaves, the NO 3 :NH 4 ratio in the plant induction medium, small explants and the growth regulator combination were most important.
Abstract: A new procedure is described for rapid and efficient plant regeneration from leaf explants of Cucumis sativus and C. anguria. The following factors were most important: young leaves, the NO 3 :NH 4 ratio in the plant induction medium, small explants and the growth regulator combination. After about 4 weeks of culture under optimal growth conditions, the frequency of regeneration was 10-100% of explants. Six to 7 weeks were required to obtain well-rooted plants, which were mostly able to survive after transfer into soil. From a single young leaf of C. sativus cv. 'Borszczagowski', 135 plants could be regenerated. All plants transferred to a greenhouse were free of morphological or physiological abnormalities, flowered normally and bore fruits. The analysis of R 0 plants showed no genetic variation, whereas in the R 1 two new phenotypes, which were not transmittable to the R 2 , were observed. This procedure is recommended for its production of homogeneous cucumber plants.

Journal ArticleDOI
TL;DR: This paper suggests that the artificial supplement of GA3, hormone is needed after fertilization for the normal growth of the hybrid embryo, possibly as the natural GA3 production is restricted with alien pollinations in cultivated lentils in both F1 and backcross hybrids.
Abstract: Wild relatives are a potential source of genetic diversity to lentil (Lens culinaris Medik). The objective of this research was to obtain viable interspecific hybrids between the domesticated lentil and its wild relatives. The paper details the results of a number of interspecific crosses among L. culinaris, L. orientalis, L. odemensis, L. ervoides and L. nigricans. Viable hybrids were produced between L. culinaris × L. orientalis, L. culinaris × L. nigricans, L. culinaris × L. ervoides and between L. culinaris × L. odemensis. Further viable hybrids were obtained between L. culinaris and L. ervoides, which have the potential to be a ‘bridge’ in hybridization to L. culinaris for specific L. nicrigans lines which proved recalcitrant in L. culinaris × L. nigricans crosses. This is the first time that four wild species of lentils have been used successfully in hybridization with cultivated lentils, and viable hybrids produced. This paper also suggests that the artificial supplement of GA3, hormone is needed after fertilization for the normal growth of the hybrid embryo, possibly as the natural GA3 production is restricted with alien pollinations in cultivated lentils in both F1 and backcross hybrids.

Journal ArticleDOI
TL;DR: It is concluded that the genetic variation observed among these accessions could be utilized in a breeding programme to develop high-yielding, well-adapted, high-oil-content noug cultivars for production in Ethiopia.
Abstract: Noug (Guizotia abyssinica Cass.), a member of the Compositae family, is grown as an oilseed crop in Ethiopia. The crop grows best on poorly drained, heavy clay soils. This study investigates the genetic variability of agronomic and seed quality characteristics of 241 noug germplasm collections from different parts of Ethiopia evaluated in a field test at Ghinchi, near Addis Ababa, Ethiopia, in 1992. The maturity of the noug accessions ranged from 132 to 168 days. Seed oil contents ranged from 39.8 to 46.9% with linoleic acid being the major fatty acid of the oil (76.6% of total fatty acids). The results of this field study indicated that genetic differences for maturity existed among the noug accessions. Oil content variation was continuous, without clear separation of accessions into oil content groups. It is concluded that the genetic variation observed among these accessions could be utilized in a breeding programme to develop high-yielding, well-adapted, high-oil-content noug cultivars for production in Ethiopia.

Journal ArticleDOI
TL;DR: A statistical model was developed based on the maximum-likelihood function for mapping of the two unlinked restorer genes and a combined genetic map was constructed which comprises 85 RAPD, five isozyme, one RFLP marker and the genes for resistance against the nematode Heterodera schachtii Schm.
Abstract: Linkage analysis of sugar beet (Beta vulgaris L.) was performed with random amplified polymorphic DNA (RAPD)-markers. From three segregating populations, a combined genetic map was constructed which comprises 85 RAPD, five isozyme, one RFLP marker and the genes for resistance against the nematode Heterodera schachtii Schm., one restorer locus for male sterility and the genes for annuality and hypocotyl colour. For mapping of the two unlinked restorer genes a statistical model was developed based on the maximum-likelihood function.

Journal ArticleDOI
TL;DR: It appeared that those hybrids whose predicted energy value from sheep measurements was low led to relatively low performances in cows, and the prediction of hybrid efficiency in dairy cow rearing must include digestibility and ingestibility factors.
Abstract: Genetic variation in the feeding efficiency of maize genotypes was evaluated from experiments with dairy cows. Maize genotypes were chosen to represent a range of digestibilities from previous experiments with standard sheep. The variation in milk yield observed with dairy cows fed genotypes with low or high digestibilities or energy values was about 1.0–2.0 kg per animal per day. Moreover, the range of variation in body weight was about 10–30 kg during the 3 months of the experiments. Hybrids with similar energy values had a similar effect on milk yield, but the intake of each hybrid could be very different when they were fed to dairy cows, even if no difference in intake had been observed in sheep. The higher silage maize intake of ‘DK265’ was mostly converted into a body weight gain rather than an increased milk yield, probably because the milk yield potential of the animals was soon reached. It appeared that those hybrids whose predicted energy value from sheep measurements was low led to relatively low performances in cows. Dairy cow performances also appeared to be related to the enzymatic solubility values of the whole plants. For maize breeders, the prediction of hybrid efficiency in dairy cow rearing must include digestibility and ingestibility factors. The most important challenge for maize breeders now will probably be the adjustment of a criterion for predicting intake because the stover digestibility and the starch content can be predicted reliably with the use of NIRS calibrations.

Journal ArticleDOI
TL;DR: Evaluation of wheat lines and all possible crosses among their F1 and F3 generations revealed that two partially recessive genes conferred the resistance to Karnal bunt in ‘Pigeon’, whereas four partially dominant genes were present in the other genotypes.
Abstract: The mode of inheritance and allelic relationships among genes conferring resistance to Karnal bunt were studied in seven bread-wheat (six resistant and one susceptible) genotypes. The resistant genotypes originated in China (‘Shanghai#8’), Brazil (PF71131), the USA (‘Chris’), and Mexico (‘Amsel’, CMH77.308 and ‘Pigeon’). The susceptible line WL711 was from India. Evaluation of these wheat lines and all possible crosses among their F1 and F3 generations (about 100 progenies in each cross) revealed that two partially recessive genes conferred the resistance to Karnal bunt in ‘Pigeon’, whereas four partially dominant genes were present in the other genotypes. ‘Chris’, ‘Amsel’ and PF71131 carry one gene, whereas ‘Shanghai#8’ and CMH77.308 have two genes. ‘Chris’, ‘Amsel’, and PF71131 have different genes, whereas one gene was common to PF71131, CMH77.308 and ‘Shanghai#8’, and another to ‘Chris’ and CMH77.308. Gene symbols were formally designated to the resistant stocks. Resistance was incomplete and stable.

Journal ArticleDOI
TL;DR: This preliminary study indicated that the resistance to race 2 of fusarium wilt is controlled by two genes, the first of which must be present in the homozygous recessive form, and the other in the dominant form, whether homozygotes or heterozygous for complete resistance.
Abstract: This preliminary study indicated that the resistance to race 2 of fusarium wilt is controlled by two genes, the first of which must be present in the homozygous recessive form, and the other in the dominant form, whether homozygous or heterozygous for complete resistance. Early wilting results if the other gene is homozygous recessive. Late wilting occurs if both loci are dominant. The existence of differences among chickpea cultivars in the time taken to express the initial symptoms of fusarium wilt were observed

Journal ArticleDOI
TL;DR: The genotype IBPT-34 developed a large number of albino plants, and it should be useful as a parent in studies to determine the genetic control of alBino plants in wheat.
Abstract: Genetic variability in response to anther culture was investigated in 49 winter hexaploid wheats, comprising 33 pure lines (F10) derived from a composite cross programme and their 16 parental genotypes. All genotypes were grown in a randomized block design with three replications in a controlled greenhouse. The number of embryoids and total plant regeneration per 100 anthers, as well as the numbers of green and albino plants regenerated per 100 embryoids, were measured. Significant genetic variability was observed among the 49 genotypes for all the traits studied. All traits showed high heritability. Among the genotypes compared, DC230N and 1BPT-40 gave the best results for the production of embryoids and IBPT-78 had the highest value for the production of green plants. The genotype IBPT-34 developed a large number of albino plants, and it should be useful as a parent in studies to determine the genetic control of albino plants in wheat.

Journal ArticleDOI
TL;DR: The data demonstrated that gene transfer from S. arvensis to B. napus was very difficult under controlled cross and backcross, while to transfer genes from B.Napus to S.Arvensis would be extremely remote even under the most favorable conditions.
Abstract: The possibility of gene transfer between Brassica napus and Sinapis arvensis was evaluated. Six spring-type cultivars of B. napus and four strains of S. arvensis were reciprocally crossed through controlled crosses. No hybrid was yielded from any cross. However, one hybrid with 28 chromosomes was obtained from B. napus x S. arvensis through ovule culture. The hybrid plant was highly sterile and set no seed on open pollination. Two F 2 plants, with 35 and 36 chromosomes respectively, were obtained through self-pollination by hand. Backcross of B. napus produced 23 plants carrying some characteristics of S. arvensis, but backcross to S. arvensis failed to produce a plant. The chromosome counts of the BC 1 F 1 plants indicated that gametes with more than nine chromosomes were favoured during the meiosis. The data demonstrated that gene transfer from S. arvensis to B. napus was very difficult under controlled cross and backcross, while to transfer genes from B. napus to S. arvensis would be extremely remote even under the most favorable conditions.

Journal ArticleDOI
TL;DR: HinfI-digested DNA samples of wild and cultivated species of tomato were hybridized in get to different oligonucleotide probes complementary to simple-sequence repeats to produce multilocus fingerprints in all tomato species and cultivars.
Abstract: HinfI-digested DNA samples of wild and cultivated species of tomato were hybridized in get to different oligonucleotide probes complementary to simple-sequence repeats. All motifs tested i.e. (GATA) 4 , (GGAT) 4 , (CA) 8 , (CAG) 5 , (GTG) 5 , (GAAGTGGG) 2 and (CCTA) 4 , produced multilocus fingerprints in all tomato species and cultivars. The extent of inter- and intraspecific polymorphism of the banding patterns varied considerably between different probes, with (GGAT) 4 , (CCTA) 4 , (GATA) 4 and (CA) 5 showing a much higher discriminatory potential than the other probes. Cluster analysis of band-sharing data yielded dendrograms which were consistent with the known history of tomato cultivation. (GATA) 4 was also successfully used for purity testing of breeding lines, as well as for analysing an F 1 progeny of a cross between two lines.

Journal ArticleDOI
TL;DR: Different amounts and numbers of applications of colchicine were evaluated in two experiments to exploit this natural propensity towards diploidization in this phase, to induce an acceptable yield of gynogenic embryos from unfertilized ovary and flower cultures in onion.
Abstract: The presence of 2,4-dichlorophenoxyacetic acid (2,4-D) or naphthaleneacetic acid (NAA) and 6-benzyladenine (6—BA) in the medium is required to induce an acceptable yield of gynogenic embryos from unfertilized ovary and flower cultures in onion. Four different exposure times of ovary and flower cultures to exogenous growth regulators (15, 30, and 45 days, and the entire culture period) were assayed. The objective was to ascertain the effect of these substances and of their period of application on the formation of gynogenic embryos and on the yield of haploids. An exposure of 15 days was sufficient for ovaries and flowers to be stimulated towards the gynogenic response, whereas, for the remaining period of 30—80 days, the pro-embryos could easily grow on a growth-regulator-free medium. In the gynogenic material obtained, phenotypic differences were visible between genetically independent lines but not between plants within each line, even when they had a different ploidy level (n or 2n). Almost all lines obtained by gynogenesis were sterile. Only a small percentage (1%) became fertile through spontaneous chromosome doubling, and these produced 2—20 seeds each, giving normal plants. The recovery of fertility occurred more often during the generations of bulbils. To exploit this natural propensity towards diploidization in this phase, different amounts and numbers of applications of colchicine were evaluated in two experiments. The treatments corresponding to 10 and 100 mg/1 of colchicine applied for 24h gave the highest number of diploid cells in root tips but no diploidization occurred in the shoot apices. Three days of colchicine treatment at 10 mg/1 produced 46% of plants completely diploid in the shoot apex. The flower fertility of these doubled haploid plants is being evaluated.

Journal ArticleDOI
TL;DR: The resistance to Leveillula taurica from an african pepper line H3 (Capsicum annuum) was evaluated and analysed, using the androgenetic haplodiploid progeny from an F 1 hybrid between H3 and a susceptible line, confirming the high level and stability of this resistance source in Mediterranean countries.
Abstract: The resistance to Leveillula taurica from an african pepper line H3 (Capsicum annuum) was evaluated and analysed, using the androgenetic haplodiploid progeny from an F 1 hybrid between H3 and a susceptible line. Tests were performed in natural infection conditions in two locations (France and Sicily). Stable behaviour of the parental and haplodiploid lines was observed in both locations, confirming the high level and stability of this resistance source in Mediterranean countries. Heritability of resistance was high and genetic analysis suggested that it is under oligogenic control. However, the number of genetic factors involved in resistance depended on infection conditions: two or three genetic factors with additive and partial dominance effects appear sufficient to confer resistance at the beginning of the epidemic or in weak infection conditions. However, additional genes are necessary to slow down further disease progress and secondary infections and at least five genetic factors are necessary to confer resistance in severe infection. In this case, both additive and epistatic effects are significant. The transfer of this resistance into cultivars will require the use of artificial inoculation procedures to control the severity of the test.

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TL;DR: A collection of 299 secondary hexaploid triticale cultivars and advanced breeding lines from 18 countries, which were considered a representative sample of the existing diversity, was evaluated for morphological and agronomical characters with autumn planting at Lleida, Spain, from 1988 to 1991.
Abstract: A collection of 299 secondary hexaploid triticale cultivars and advanced breeding lines from 18 countries, which were considered a representative sample of the existing diversity, was evaluated for morphological and agronomical characters with autumn planting at Lleida, Spain, from 1988 to 1991. The entries were classified as having winter (84) or spring (215) growth habit and among this latter group were complete (73) or substituted (147) types according to CIMMYT's terminology. Winter and spring triticales were grouped by cluster and principal component analyses. Winter triticales were taller with longer growth cycles, longer spikes, and more spikelets per spike than spring types. At early stages they also had prostrate growth. Spring-substituted types were separated from complete material. As a group, spring-substituted triticales differed more from winter types than the spring complete genotypes, which showed intermediate characteristics. Complete types of spring habit had tendency to be taller, with longer spikes, more spikelets per spike and bigger and heavier grains than substituted triticales. Greater variation in morphological and agronomical parameters was detected among winter triticales followed by the complete-spring group.