Genetic divergence study of 42 genotypes of rice for 20 agronomic, physiological and quality traits led to their grouping into 12 clusters. Grouping of the genotypes from different eco-geographical regions into one cluster and from the same location into different clusters indicated non-parallelism between geographical distribution and genetic diversity. Highest contribution to the genetic diversity was through 100 grain weight followed by volume expansion ratio, kernel length, days to 50% flowering and plant height. The clusters XI and XII were highly divergent. The other clusters with moderate divergence and having single genotypes were VI, VII, VIII, and IX. Based on the inter-cluster distance, mean performance and clustering pattern, hybridization between Tellahamsa, Shiva, WGL-NDL2, Erramallelu, Lunisree, RDR763 and IR20 is likely to give recombinants having high yield potential and high grain quality.
Relationship between carliness and other yield components were analyzed in 20 crosses involving four early and five very early lines in indica rice. Earliness (days to flowering) had significant and positive correlation with most of the characters studied. Positive significant association was observed among the yield components. Correlation studies revealed that selection for very early types obviously resulted in reductin in panicle length, number of grains and 100 grain weight which in turn reduced the yield.
MGR (CORH1) rice hybrid was developed using cytoplasmic genic male sterile line, maintainer line and restorer line (A/B/R). The parentage of this hybrid is IR 62829 A/IR10198-66-2R. This matures in 110-145 days, grows to a height of 75 cm and tillers profusely under a wider spacing of 25 x 10 cm. The average grain number is 150 per panicle and 1000 grain weight is 20 g. It gives one tonne more yield per hectare over IR 50. The grain is medium slender, straw coloured with white rice. This is best suited for May-June and December - January sowings in Tamil Nadu.
Nine parents and twenty hybrids of rice (Oryza satival.) were evaluated for heterosis for days to flowering, plant height, number of productive tillers, panicle length, number of grains per panicle, 100 grain weight and grain yield. Hybrids showing negative heterosis for flowering duration recorded positive heterosis for yield components. Significant standard heterosis for other traits was also observed. We can expect to develop hybrids from the parental lines possessing carliness for higher yield components.
The combining ability and heterosis were estimated from a number of crosses comprising 10 elite varieties of Zea mays L. obtained from diverse geographical regions. 'AB male bulk' was the best general combiner for grain yield and kernel/row. Two single crosses viz AB male bulk x composite V2' and 'Hemant x CIMMYT Pool 23' significantly outyielded the standard check "Vijay Composite', and the hybrid check 'Deccan 103. for grain yield. The extent of heterosis over better parent and economic heterosis revealed that crosses which had higher estimates of heterosis for grain yield also exhibited higher estimates of heterosis for the major yield components as well.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.