Twenty five rice varieties were evaluated for their variability with regard to yield and yield components. Estimates of heritability and genetic advance as per cent mean were also obtained for the above traits. In addition, studies on character associations and path co-efficients were also undertaken. The results revealed high variability, heritability and genetic advance as per cent mean for productive tillers per plant, number of tillers per plant, number of grains per panicle and number of filled grains per panicle, while days to maturity was recorded with high heritability coupled with low genetic advance as per cent of mean. Further, yield was observed to be positively associated with number of tillers per plant, productive tillers per plant, number of grains per panicle and number of filled grains per panicle. Among these, number of tillers per plant, productive tillers per plant and number of filled grains per panicle were noticed to exert high direct effects on grain yield per plant. High indirect effects of most of the traits were noticed mostly through productive tillers per plant indicating importance of the trait as selection criteria in crop yield improvement programmes.Bangladesh J. Agril. Res. 41(2): 259-271, June 2016

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The study consists of fifty-nine blackgram genotypes, which were evaluated for fourteen quantitative and qualitative traits. In order to determine the relationship and diversity among the blackgram genotypes taken for study. A field experiment was conducted at the Regional Agricultural Research Station, Lam, Guntur district, Andhra Pradesh state during Kharif, 2019. Principal component analysis for various yield-contributing traits was done to evaluate diversity and some quantitative and qualitative traits that had more effects on diversity. PCA results revealed that four of the five principal components had eigen values greater than one. The first five components obtained from principal component analysis (PC 1 to 5) accounted for about 76.73% of the total variation for fourteen quantitative and qualitative traits. Out of total principal components, PC 1, PC 2, PC 3, PC 4 and PC 5 were retained with values of 35.42%, 14.85%, 11.14%, 8.75% and 6.56%, respectively. The results of 2D and 3D scatter diagrams revealed LBG 904, LBG 752 and TU 94-2 genotypes to be the most diverse. Utilizing these diverse genotypes as parents in hybridization suggests obtaining desirable transgressive segregants towards the development of high yields with nutritional quality. The clustering of blackgram genotypes based on the yield and quality-attributing traits would be helpful in identifying the appropriate genotypes for effective utilisation in upcoming breeding programmes. The outcomes of principal component analysis revealed that wide genetic variability occurs between these blackgram genotypes and proposed their potential value in blackgram yield and quality improvement.

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Studies on seasonal incidence of sucking insect pests carried out with three dates of sowing viz., early (July 15th), normal (July 30th) and late (August 15th) revealed that the incidence of leafhoppers, aphids and thrips started from 5 to 14 DAS (days after sowing) and continued till harvesting. In early sown crop, the incidence of leafhoppers started from 31 SW and incidence of aphids and thrips started from 30 SW and continued up to 42 and 43 SW for leafhoppers and aphids, respectively and 41 SW for thrips. In normal sown crop, incidence of leafhoppers and aphids started from 32 SW and incidence of thrips started from 31 SW and continued till the end of 45 SW for all the three pests. In late sown crop, the incidence of leafhoppers started from 35 SW and incidence of aphids and thrips started from 34 SW and continued up to 46 and 47 SW for leafhoppers and aphids, respectively and 46 SW for thrips. Correlation studies revealed that incidence of leafhoppers exhibited significant negative correlation with maximum temperature (r = -0.467, -0.442 and -0.464) and rainfall (r = -0.518, -0.529 and -0.742) during all the three dates of sowing (early, normal and late, respectively) and significant negative correlation with minimum temperature in late sown crop (r = -0.448). Aphids exhibited significant negative correlation with maximum temperature (r = -0.469, -0.521 and -0.472) and rainfall (r = -0.443, -0.450 and  -0.721) in all the three dates of sowing (early, normal and late, respectively) while significant negative correlation with minimum temperature in early and late sown crop with r values -0.519 and -0.324.  Thrips exhibited significant positive correlation with maximum temperature (r = 0.522, 0.459 and 0.447), significant negative correlation with rainfall (r = -0.458, -0.465 and -0.451) during three dates of sowing (early, normal and late, respectively) while significant negative correlation with relative humidity in early sown crop (r = -0.616) and significant positive correlation with minimum temperature in early sown crop (r = 0.463).