No abstract

A group of 30 strains of black gram collected from different geographic regions of India was studied to analyse the extent of genetic divergence using Mahalanobi's D' technique. The strains got grouped into eight clusters and the clustering pattern was independent of geographic distribution. Characters, pod yield and seeds/pod were found to be important contributors to genetic divergence.

The pearlmillet hybrid TNBH 5635 (732 A x PT 4450) was released as COHCu 8 during January 2001 for general cultivation in Tamil Nadu. It recorded a mean grain yield of 2819 kg ha-1 (21.7% over X7) under rainfed conditions and 3682 kg ha-1 (15.0% over X7) under irrigated conditions. It is resistant to downy mildew and possess 5-8 productive tillers with nonlodging and spindle type ear heads. The protein content is about 13.8 per cent with acceptable cooking quality. It can be grown in June" - July, September October and January February throughout Tamil Nadu and is the best alternative to X7 hybrid.

Forty drought tolerant rice genotypes were used to study genetic variability, character association and path analysis between yield and its contributing traits under semi-dry cultivation in two environments. Irrespective of the environment, high phenotypic and genotypic coefficients of variation coupled with high heritability and high genetic advance in spikelet sterility and leaf area index indicated the predominance of additive gene effects in controlling them. Difference in GCV estimates over the environments was found to be a good tool to find out favourable environment to exploit genotypic variation and to exercise selection for improvement of traits. Productive tiller number, harvest index and drymatter production had positive and significant correlation with yield in both environments. Harvest index and drymatter production showed positive and direct effect on yield, and a negative indirect effect on each other with yield.