M. Allahgholipour

Bio: M. Allahgholipour is an academic researcher from Rice University. The author has an hindex of 1, co-authored 1 publications receiving 16 citations.

Gene Action and Combining Ability for Grain Yield and Its Components in Rice

Abstract: In this study, an effort was made to identify good parents and nature of gene action governing different characters of rice by line (4 restorers) × tester (2 cytoplasmic male sterile lines) analysis. The trial comprising 8 hybrids and their parents were laid out in randomized block design with 3 replications and characterized for yield and nine yield component traits. In the present study, the ANOVA for combining ability revealed significant differences between the treatments (genotype) for all the traits studied and amongst the treatments the mean sum of square (MSS) due to parents showed significant differences for all the traits. The grain yield, grain number per panicle, plant height and days to fifty percent flowering appears to be the key determining traits and showed significant differences for the lines, testers, line × testers. Parents with low × high general combining ability (GCA) effects resulted in heterotic hybrid combination like the IR68281A/IR68749R. Interestingly, we found low ×...

An Introduction to Genetic Statistics

Abstract: A reviewer for the Journal of the Royal Statistical Society of England comments \"This is the first book covering in one volume all important topics in genetical statistics.\" Written to provide basic probability ideas in terms of genetic situations, since the theory of genetics is a probability theory; to give a definitive treatment of applications of these ideas to genetic theory; and to describe statistical methods appropriate to the data models that are developed.

Introgression of bacterial blight resistance genes Xa7, Xa21, Xa22 and Xa23 into hybrid rice restorer lines by molecular marker-assisted selection

Abstract: Four bacterial blight (BB) resistance genes, Xa7, Xa21, Xa22 and Xa23, were introgressed into an elite hybrid rice restorer line Huahui 1035, by marker-assisted selection (MAS). Ten promising BB resistant lines identified by MAS approach in Huahui 1035 restorer background and their respective F1 hybrids with a cytoplasmic male sterile line i.e. Jinke 1A, three BB resistant gene donors and their recurrent parent were evaluated for BB resistance by inoculating them with eleven representative races of Xanthomonas oryzae pv. oryzae (Xoo) in China. Further, the ten marker assisted selection of BB (MAS-BB) resistant restorer lines and their F1 hybrids were also characterized for agro-morphological traits and grain yield. Results revealed that restorer lines with Xa23 introgression i.e. HBQ809 and HBQ810 were found to be resistant to all eleven Chinese representative Xoo races, showing broad spectrum resistance to BB. However, the lines possessing Xa7 or Xa7+Xa21 were resistant to ten out of eleven Xoo races. While restorer lines with Xa21 were resistant to nine out of eleven Xoo races. Interestingly, the F1 hybrids with Xa23, Xa7 or Xa7+Xa21 were resistant to two severe epidemic Xoo races of China. Restorer lines i.e. HBQ807 and HBQ808 possessing Xa22 were only resistant to six or five out of inoculated eleven Xoo races. Lesion length comparisons between restorer lines and their F1 hybrids for the above four BB resistance genes showed them to be dominant in heterozygote genotype. Three promising high yielding F1 hybrids with BB resistance were identified for immediate exploitation for hybrid rice production in China.

Tagging of four fertility restorer loci for wild abortive—cytoplasmic male sterility system in rice (Oryza sativa L.) using microsatellite markers

Abstract: Tagging of restorer genes for wild abortive (WA) CMS source by studying a 222 individual plants from a F2 population of a cross between IR58025A × IR42686R The restorer line IR42686R that was used in this study had been previously derived through random mating composite population (RMCP) involving 12 parents facilitated by IR36 genetic male sterility Four Rf genes were tagged to simple sequence repeats (SSR) markers on chromosomes 1, 7, 10, 12 by recessive class analysis The recombination frequency between a positive marker and Rf locus was calculated using maximum likelihood estimator assuming that all the 46 extremely sterile individual plants were homozygous at the targeted Rf locus The recombination frequency between the marker and the restorer trait were converted to genetic distances using Kosambi function A new Rf locus designated as Rf7 on chromosome 12 was found to be linked to RM7003 at a genetic distance of 133 cM (LOD 612) We report here first, a new molecular marker (RM 6344) linked to Rf4 locus on chromosome 7 that was previously mapped by trisomic analysis RM443 and RM315 were flanking the Rf3 gene at a genetic distance of 44 (LOD 1029) and 207 cM (LOD 398) on chromosome 1, respectively The Rf6 was flanked on both side with SSR markers RM258 and RM591 at a genetic distance of 44 (LOD 1029) and 233 cM (LOD 339) located on chromosome 10 The random mating composite population is an excellent breeding approach to develop superior restorer lines and for pyramiding different Rf genes of different CMS systems Rf genes tagged with closely linked SSR markers would be facilitating marker assisted selection (MAS) in hybrid rice breeding program by reducing time and workload for identifying potential restorers

GENETIC ANALYSIS OF QUANTITATIVE TRAITS IN AROMATIC RICE (Oryza sativa L.)

Abstract: The present investigation was conducted to estimate the combining ability, heterosis, inbreeding depression, heritability, variability, genetic advance, correlations and path coefficients for yield components and grain quality characters crossing 8 parents in diallel design (without reciprocals) at Agricultural Research Station, Kampasagar. Further, through generation mean analysis, the nature and magnitude of non allelic interactions were investigated. Analysis of variance revealed the presence of sufficient variation in the experimental material. Through combining ability analysis, the parents, Akshyadhan, Basmati 370 and Sumathi were identified as the potential combiners for grain yield and prime component traits, panicle length, panicle weight, filled grains per panicle and 1000 grain weight. Whereas, Improved Pusa Basmati and Basmati 370 combined well for kernel characters including cooking quality traits. As such, these parents could be better utilized for breeding material generation. Among the crosses, Pusa 1121 x Sumathi, BPT 5204 x Basmati 370, Pusa 1121 x Basmati 370, BPT 5204 x NLR 145, Sumathi x Improved Pusa Basmati, RNR 2354 x Sumathi, BPT 5204 x Akshyadhan, RNR 2354 x Basmati 370, NLR 145 x Pusa 1121 and Akshyadhan x Pusa 1121 for different yield components; Pusa 1121 x Sumathi, BPT 5204 x RNR 2354 and BPT 5204 x Basmati 370, Pusa 1121 x Sumathi and Akshyadhan x Improved Pusa Basmati for kernel quality characters were identified as the best specific crosses in view of their high per se performance, sca effects and gca of their respective parents. Significant heterosis over mid and better parents was observed in many cross combinations. The crosses, Akshyadhan x Pusa 1121, Akshyadhan x Sumathi, NLR 145 x Pusa 1121 and RNR 2354 x Improved Pusa Basmati exhibited highly significant heterosis and heterobeltiosis for yield and component characters besides earliness. The other promising crosses for both yield components and quality traits were NLR 145 x Basmati 370, Sumathi x Improved Pusa Basmati, Pusa 1121 x Sumathi and Akshyadhan x Improved Pusa Basmati. High heterosis in F1 generation was accompanied by high inbreeding depression in F2 generation for the prime yield component, grains per panicle, whereas, the inbreeding depression was very low for panicle weight and 1000 grain weight. Hence, direct selection for yield improvement through these two characters would be highly beneficial. Considering this point, Akshyadhan x Pusa 1121 for yield potential and BPT 5204 x RNR 2354 and Akshyadhan x Basmati 370 for good cooking qualities with aroma were recommended for straight selection. Generation mean analysis was performed to detect the epistasis and estimate 5 components (m, d, h, i and l) as per 5 parameter model. The C and D scaling tests and the joint scaling test (3 parameter model) confirmed that the additive dominance model was inadequate to explain the inheritance of these characters. Based on the magnitudes of fixable genetic variation (‘d’ & ‘i’ types) and per se, pedigree selection in segregating generations with respect to crosses, BPT 5204 x Sumathi, RNR 2354 x Basmati 370 and Sumathi x Improved Pusa Basmati (for yield and quality) and BPT 5204 x Akshyadhan, Akshyadhan x NLR 145, Akshyadhan x Pusa 1121 (for grain yield) and BPT 5204 x Pusa 1121, Improved Pusa Basmati x Basmati 370 (for quality alone) was recommended. In F2 and F3 generations, among the yield characters, highest PCV and GCV values were recorded for no. of filled grains/panicle followed by grain yield and panicle weight indicating greater scope of obtaining high selection response for these traits. High heritability (F2 and F3) along with medium to high genetic advance was noticed for the trait, 1000 grain weight and most of the kernel traits, which facilitates direct selection in segregating populations for development of pure lines with good yield potential and quality. Eleven crosses with high per se performance, heterosis coupled with less inbreeding depression were carefully choosen and genetic parameters viz., GCV, PCV, h (bs) and GA) were estimated to suggest suitable breeding techniques on cross wise basis. Based on these results, direct selection for yield improvement in two crosses viz., Sumathi x Basmati 370 and Akshyadhan x NLR 145 and for quality improvement in five crosses viz., NLR 145 x Pusa 1121, Pusa 1121x Sumathi, Pusa 1121x Improved Pusa Basmati, Sumathi x Improved Pusa Basmati and Improved Pusa Basmati x Basmati 370 was considered as highly feasible and recommended. A critical analysis of both character association and path analysis in F1, F2 and F3 indicated that, among the yield components investigated, panicle weight and no. of filled grains/panicle are very important, as the correlation coefficients as well as the direct effects were high irrespective of the generation. The results of the present study revealed that the nature and magnitude of gene effects differ depending on the cross and character under consideration. Hence, apart from direct selection, the other procedures like recurrent selection or biparental mating in early segregating generations to poolup desired genes is also recommended depending on the cross combination. Taking into consideration the whole genetic analysis through the present investigation, pedigree selection in the cross combinations, Akshyadhan x Pusa 1121, NLR 145 x Pusa 1121 and BPT 5204 x NLR 145 for grain yield and Akshyadhan x Improved Pusa Basmati and Pusa 1121 x Sumathi for kernel dimensions (length, L/B ratio) and BPT 5204 x RNR 2354 and Akshyadhan x Basmati 370 for cooking quality characters was considered as most feasible and rewarding. In respect of other superior crosses, instead of direct selection biparental mating in F2 generation followed by selection was recommended alternatively.