R. F. Holland

Bio: R. F. Holland is an academic researcher. The author has contributed to research in topics: Cytoplasmic male sterility. The author has an hindex of 1, co-authored 1 publications receiving 189 citations.

Cytoplasmic Male‐Sterility For Hybrid Sorghum Seed Production1

Abstract: NVES'TIGATIONS with three-way crosses as a method 1 for hybrid sorghum seed production have been reported previ~usly.~ All possible crosses between heterozygous (Msms) Day, Double Dwarf Yellow Sooner milo and Texas Blackhull kafir were made to determine if cytoplasmic factors might account for the F, male-sterility in the combination of msms Day x kafir. The evidence indicated that the F, sterility was genetic rather than cytoplasmic. The F, plants of milo x kafir and its reciprocal grown in 1949 were fully fertile. However, some partial male-sterility was observed the following year in small F, populations of milo x kafir but not in the reciprocal cross, kafir x milo. The defective anthers in partially male-sterile panicles were somewhat longer than those typical of malesterile Day. In the same year, in certain progenies of ms Day x kafir, F, male-sterile, crossed with various combine kafirs, some rows segregated in a ratio of approximately one fertile to one male-sterile as expected. However, most of the plants in other rows were sterile or partially sterile. Part of the plants in rows having excess male-sterility had the long, pinched-appearing anthers observed in the F,2 plants of milo x kafir. Since Day is derived from milo and presumably has milo cytoplasm, it was reasoned that the unexpected sterility might be accounted for if some degree of cytoplasmic male-sterility was being expressed in part of the populatioas. N o seed stocks of cytoplasmic male-sterile lines for distribution to producers have been developed but the results obtained 1:hrough 1952 warrant a preliminary report. Considerable interest in this material has been shown by visitors who have inspected the experiments in progress at this Station.

The inviability, weakness, and sterility of interspecific hybrids.

Abstract: Publisher Summary In this chapter, the review of available data clearly points to the conclusion that the causes underlying the erection of barriers of reproductive isolation, therefore of the origin of species, differ considerably from one group of organisms to another. Furthermore, these differences are related to other differences among groups of organisms, such as size and structure of populations, rates of reproduction, and methods of adaptation. In the future, therefore, the study of the origin of species should not be a search for any more general causes, which might be considered as responsible for speciation in all groups of organisms, but a series of special and comparative investigations, by means of which the interrelationships mentioned above, as well as others as yet unknown, can be further explored and more firmly established.

Cytoplasmic male sterility.

Abstract: Cytoplasmic inheritance is of theoretical importance-it may be of even greater practical importance, for, when it involves malesterility-as in many instances it does-it may make hybridization easier. It may also make possible the use of heterosis in plants otherwise difficult to hybridize. The effect of the cytoplasm on the inheritance of male-sterility was speculated on before the rediscovery of Mendel's Laws:

Cytoplasmic male sterility (CMS) in hybrid breeding in field crops

Abstract: A comprehensive understanding of CMS/Rf system enabled by modern omics tools and technologies considerably improves our ability to harness hybrid technology for enhancing the productivity of field crops. Harnessing hybrid vigor or heterosis is a promising approach to tackle the current challenge of sustaining enhanced yield gains of field crops. In the context, cytoplasmic male sterility (CMS) owing to its heritable nature to manifest non-functional male gametophyte remains a cost-effective system to promote efficient hybrid seed production. The phenomenon of CMS stems from a complex interplay between maternally-inherited (mitochondrion) and bi-parental (nucleus) genomic elements. In recent years, attempts aimed to comprehend the sterility-inducing factors (orfs) and corresponding fertility determinants (Rf) in plants have greatly increased our access to candidate genomic segments and the cloned genes. To this end, novel insights obtained by applying state-of-the-art omics platforms have substantially enriched our understanding of cytoplasmic-nuclear communication. Concomitantly, molecular tools including DNA markers have been implicated in crop hybrid breeding in order to greatly expedite the progress. Here, we review the status of diverse sterility-inducing cytoplasms and associated Rf factors reported across different field crops along with exploring opportunities for integrating modern omics tools with CMS-based hybrid breeding.

Functioning and Variation of Cytoplasmic Genomes: Lessons from Cytoplasmic–Nuclear Interactions Affecting Male Fertility in Plants

Abstract: Publisher Summary The generality of cytoplasmic male sterility (CMS) suggests that understanding its basis may give the fundamental information about cytoplasmic genomes functioning in plant development. This chapter describes the male sterility in Petunia, maize, sorghum, sugarbeet, Nicotiana, Vicia faba, sunflower, Solanum, cruciferous species, pearl millet, carrot, wheat and rye, and barley. In some CMS systems, identification of a CMS-specific DNA sequence and its products may immediately reveal why microspores or male reproductive tissues do not develop properly. However, mere identification of a CMS-correlated gene and protein of unknown function would not reveal the mechanism of CMS without further cytological, biochemical, and physiological studies. As functions of mitochondrial-encoded polypeptides have become known, new models for CMS mechanisms may arise. Such models could most readily be tested if cloned Mitochondrial DNA (mtDNA) sequences could be introduced anew into mitochondrial genomes. The underlying mechanisms of CMS are likely to be as diverse as the abnormal reproductive phenotypes observed within and among species.

Genetic diversity of public inbreds of sorghum determined by mapped AFLP and SSR markers.

Abstract: The objectives of this study were (i) to assess the level of genetic diversity in elite sterility-maintaining (B) and fertility-restoring (R) sorghum [Sorghum bicolor (L.) Moench] lines as compared with a group of exotic and converted germplasm (IS) from the World Collection, (ii) to compare the classification of germplasm on the basis of estimates of genetic similarities obtained by means of AFLP and microsatellite (SSR) markers, and (iii) to compare the classification of germplasm obtained by different classes of molecular markers. A set of 100 SSRs, 1318 EcoRI/Msel AFLP, and 496 PstI/MseI AFLP markers with known map positions were utilized to determine the genetic similarity in a group of B, R, and IS public inbreds. Cluster analysis of genetic similarity estimates (GS ij ) revealed that the classification of sorghum inbreds is based on the sorghum working groups, Zera-zera, Kafir, Kafir-Milo, Durra, and Feterita. Cluster analyses failed to give a clear differentiation between B- and R-lines, suggesting that R- and B-lines do not represent well-defined heterotic groups in this set of public lines. By comparing the different classes of molecular markers (SSRs, AFLPs, combinations of SSRs and AFLPs), we determined that the distribution of the markers and the coverage of the genome by the markers did affect the classification of genotypes. Dendrograms of genetic similarity (GS) based on PstI/MseI AFLP markers, or a set of markers spaced at 1- to 2-cM intervals across the genome, produced clusters that were in better agreement with pedigree information than the analysis based solely on the EcoRI/ Msel AFLP or SSR markers used in this study.