Despite significant yield advantage over inbred rice, the adoption rate of hybrid rice in India is very low due to the high seed cost and poor quality of the produce. To alleviate the problem, we initiated a doubled h...Despite significant yield advantage over inbred rice, the adoption rate of hybrid rice in India is very low due to the high seed cost and poor quality of the produce. To alleviate the problem, we initiated a doubled haploid （DH） breeding approach to develop new lines from two elite indica rice hybrids （CRHR5 and CRHR7） through rapid fixation of homozygosity in the recombinants. In vitro culture of the rice anthers resulted in 243 and 186 fertile DH lines of CRHR5 and CRHR7, respectively. Flow cytometric and pollen fertility analyses confirmed the DH ploidy status of the regenerations. Morpho-agronomic evaluation revealed 100% uniformity and stability for all the characters in the DH lines of both hybrids. Nineteen promising DH lines of each hybrid were advanced to A2 generation for yield evaluation. The yield levels of the DH lines ranged from 5 097-6 965 kg/hm^2 for CRHR5 and 5 141-7 235 kg/hm^2 for CRHR7, which were at par or higher than the parental hybrids. Physico-chemical characterization and cooking quality analyses revealed significant and acceptable values for grain length and width, alkali spreading value, amylose content and water uptake ratio of the selected DH lines. Three DH lines, CR5-10, CR5-49, CR5-61 from CRHR5, and four DH lines, CR7-5, CR7-7, CR7-12 and CR7-52 from CRHR7, showed significant grain yield and quality characteristics and have been recommended for multi-location trials for subsequent release as new indica doubled haploid rice varieties.展开更多
Trifolium alexandrinum, an important forage legume, suffers from narrow genetic base. The present investigation was envisaged to reveal the inter- and intra-species genetic diversity and lineage among 64 accessions, r...Trifolium alexandrinum, an important forage legume, suffers from narrow genetic base. The present investigation was envisaged to reveal the inter- and intra-species genetic diversity and lineage among 64 accessions, representing a global collection, of T. alexandrinum;it’s two probable progenitor species (T. salmoneum and T. subterraneum) and the three genetically distant species (T. repens, T. vesiculosum, T. michelianum). A set of Simple Sequence Repeats (SSR) primer-pairs developed from T. alexandrinum have shown to amplify alleles across the species under study, suggesting utility of the newly developed resource for assessing molecular diversity among Trifolium species. These SSRs markers together with previously reported SSRs, derived from T. repens, enabled to reveal high intra-species polymorphism in T. alexandrinum and successfully discriminate different species investigated in this study. The diverse accessions determined herein provide a superior resource for further breeding of T. alexandrinum. High allelic similarity of T. alexandrinum with T. subterraneum and T. salmoneum indicated close relatedness among the species, suggesting polyphyletic evolution of T. alexandrinum.展开更多
文摘Despite significant yield advantage over inbred rice, the adoption rate of hybrid rice in India is very low due to the high seed cost and poor quality of the produce. To alleviate the problem, we initiated a doubled haploid （DH） breeding approach to develop new lines from two elite indica rice hybrids （CRHR5 and CRHR7） through rapid fixation of homozygosity in the recombinants. In vitro culture of the rice anthers resulted in 243 and 186 fertile DH lines of CRHR5 and CRHR7, respectively. Flow cytometric and pollen fertility analyses confirmed the DH ploidy status of the regenerations. Morpho-agronomic evaluation revealed 100% uniformity and stability for all the characters in the DH lines of both hybrids. Nineteen promising DH lines of each hybrid were advanced to A2 generation for yield evaluation. The yield levels of the DH lines ranged from 5 097-6 965 kg/hm^2 for CRHR5 and 5 141-7 235 kg/hm^2 for CRHR7, which were at par or higher than the parental hybrids. Physico-chemical characterization and cooking quality analyses revealed significant and acceptable values for grain length and width, alkali spreading value, amylose content and water uptake ratio of the selected DH lines. Three DH lines, CR5-10, CR5-49, CR5-61 from CRHR5, and four DH lines, CR7-5, CR7-7, CR7-12 and CR7-52 from CRHR7, showed significant grain yield and quality characteristics and have been recommended for multi-location trials for subsequent release as new indica doubled haploid rice varieties.
文摘Trifolium alexandrinum, an important forage legume, suffers from narrow genetic base. The present investigation was envisaged to reveal the inter- and intra-species genetic diversity and lineage among 64 accessions, representing a global collection, of T. alexandrinum;it’s two probable progenitor species (T. salmoneum and T. subterraneum) and the three genetically distant species (T. repens, T. vesiculosum, T. michelianum). A set of Simple Sequence Repeats (SSR) primer-pairs developed from T. alexandrinum have shown to amplify alleles across the species under study, suggesting utility of the newly developed resource for assessing molecular diversity among Trifolium species. These SSRs markers together with previously reported SSRs, derived from T. repens, enabled to reveal high intra-species polymorphism in T. alexandrinum and successfully discriminate different species investigated in this study. The diverse accessions determined herein provide a superior resource for further breeding of T. alexandrinum. High allelic similarity of T. alexandrinum with T. subterraneum and T. salmoneum indicated close relatedness among the species, suggesting polyphyletic evolution of T. alexandrinum.
