Fourteen indica rice genotypes studied for the genetic diversity were grouped into five clusters by Mahalanobis D2 analysis. Cluster I consisted of ten genotypes, cluster II, III, IV and V consisteed of single genotype each viz. ADT 40, CR 1009, HA 891037 and Improved White Ponni respectively. Filled grains number per panicle followed by days to 50 per cent flowering contributed the maximum to the genetic divergence. Cluster III exhibited relatively high mean value for days to 50 per cent flowering and grain yield. The highest contribution to the maximum divergence was made by filled grains number per panicle followed by days to 50 per cent flowering and plant height. Hybrids between parents from inter clusters produced higher heterosis than the parents from intra cluster.
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.
Background: In view of developing early maturing groundnut that fit in high intensity multiple cropping system the present study was taken up to introgress early maturing traits in the well-established high yielding varieties.
Methods: VRI 8, CO 7, ICGV 07222 and VRI 6 were takenas the variety to be improved and as a source for early maturity and male parent in the study viz., VRI 3, Chico, ICGV 91114 and ICGV 93468 were used. A crossing program was designed using these parent materials and selected crosses were forwarded to the next F2 generation and their backcross populations were also generated. The data recorded were subjected to Generation mean analysis and association analysis.
Result: With consideration of early maturity and high pod yield the genotypes F2 of CO 7 × Chico and ICGV 07222 × Chico and B2 of ICGV 07222 × Chico recorded high mean values for the traits. The presence of duplicate epistasis was observed for, days to accumulation of 25 flowers (DTF) and days to maturity. This indicates that, inter-mating the selected segregating generations could result in the accumulation of favourable genes. The trait pod yield per plant exhibited positively significant correlation with days to accumulation of 25 flowers, days to maturity in all the crosses and the trait days to accumulation of 25 flowers is positively correlated to days to maturity. Thus, the trait-days to accumulation of 25 flowers is the major selection factor for early maturity in groundnut.
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