Principal Component and Cluster Analyses in Pigeonpea [Cajanus cajan (L.) MillSp].

Forty nine genotypes of pigeonpea representing the broad spectrum of variation were assessed for twelve characters using principal component analysis and cluster analysis. These genotypes were grouped into 8 clusters by using cluster analysis. Principal component analysis identified five principal components with eigen values more than one which contributed 80.10 per cent of the cumulative variance. The genotypes LRG-41 and SM- 97, MRG-1001, WRG 51-Y, RST-16 and ICP 7035 were selected from the above analysis appeared to be desirable for inclusion in crossing programme aimed for improvement of pigeonpea.

Studies on Selection Indices in Pigeonpea [Cajanus Cajan (L.) Millsp].

Success of any breeding programme depends on the efficiency of selection. Hence, the knowledge of nature of association of various traits among themselves and with seed yield is quite important for devising an effective selection criterion for yield. The present study was carried out to assess the nature and extent of interrelationship among component traits affecting seed yield in pigeonpea (Cajanus cajan (L.) Millsp). Forty nine genotypes from different states Andhra Pradesh, Karnataka and Maharastra were evaluated in a randomized block design with three replications and the data recorded on 12 traits were subjected to statistical analysis. The correlation studies revealed the positive and significant association of seed yield with number of pods per plant, number of secondary branches per plant, number of primary branches per plant and plant height. Path analysis revealed that the number of pods per plant was important in formulating selection criteria for improvement of seed yield in pigeonpea.

Correlation Between Traits and Path Analysis Coefficient for Grain Yield and other Components in Rice (Oryza Sativa L.) Genotypes.

Current research was conducted out at the Wet land farm of S.V. Agricultural College, Tirupati during kharif, 2011 and rabi, 2011-12 crop seasons. The objective was to establish the nature of relation between grain yield and yield components by partitioning the correlation coefficients between grain yield and its components into direct and indirect effects by using simple correlation and path analysis. A correlation coefficient and path analysis study was conducted with six parents and their 15 F1 crosses for eleven component characters including grain yield. The obtained results indicated that number of grains per panicle, total number of productive tillers per plant, harvest index, kernel L/B ratio, milling percentage and panicle length showed highly significant positive association with grain yield per plant. In the path coefficient analysis, number of grains per panicle and total number of productive tillers per plant should be considered as the main yield components because these traits showed the highest positive direct effects towards increasing grain yield with the values of +0.773 and +0.572, respectively. Depending on the findings of present study, number of grains per panicle and total number of productive tillers per plant may be used an effective selection criterion to improve genetic yield potential of rice genotypes.

Comparision of cluster formation by mahalanobis’ D2 and metroglyph analyses in groundnut (Arachis Hypogaea L.).

Fifty genotypes of groundnut were classified into five and seven clusters in D2 and Metroglyph methods of analyses respectively. Harvest Index and 100-seed weight were the main contributors to total divergence as per metroglyph analysis. The characters on X and Y axes in scattered metroglyph diagram determine the grouping of genotypes, hence it poses a problem for judicious selection of these characters. The comparative study of these methods indicated that metroglyph analysis would be suitable for preliminary grouping when large number of genotypes are considered at a time. The differences between the two methods, the number of clusters formed, inter cluster distance, characters considered for grouping and superimposition of genotypes within the cluster indicated that D2 analysis was more effective compared to metroglyph analysis.

Character association and path analysis in groundnut (arachis hypogaea l.).

Correlation and path co-efficient analysis were carried out for pod yield and its component characters in 50 genotypes of groundnut. The genotypic correlation co-efficients were found to be of relatively higher magnitude than the corresponding phenotypic correlation co-efficients, indicating strong inherent association between the characters. Pod yield displayed significant positive association with kernel yield per plant, mature pods per plant, total pods per plant, harvest index, 100-seed weight, root weight, plant height and shoot weight. Path co-efficient analysis revealed high direct effects of kernel yield per plant and harvest index on pod yield. Hence, it would be rewarding to give due importance on the selection of these characters for rapid improvement in pod yield of groundnut.

Correlation and path coefficient analysis for yield and yield components in blackgram (vigna mungo (L.) hepper).

Correlation coefficient and path analysis studies was conducted with eight parents and their 28 F1 crosses for twelve component characters including seed yield and revealed significant positive association of pods per plant, harvest index and clusters per plant with seed yield in parental generation whereas in F1 generation, significant positive association of clusters per plant, pods per plant, days to maturity, days to 50% flowering, pods per cluster and 100-seed weight with seed yield was observed. Further, it was found that number of seeds per pod, harvest index, pods per plant and number of primary branches per plant showed high positive direct effects on seed yield in parents whereas in crosses, seeds per pod, pods per plant, harvest index and days to maturity showed high positive direct effect on seed yield. Hence selection based on these traits would be effective in increasing the seed yield.

Variability and genetic parameters for grain yield and its components and kernel quality attriburtes in CMS based rice hybrids (oryza sativa l.).

The present investigation was under taken to study the extent of variability and genetic parameters with 16 parents and 48 hybrids for nine yield and its components and twenty five quality characters. The magnitude of difference between PCV and GCV was relatively low for all the traits, indicating less environmental influence. High GCV and PCV were recorded for harvest index, total number of productive tillers per plant and gelatinization temperature in parents and for total number of productive tillers per plant, number of grains per panicle, gelatinization temperature and amylose content in hybrids. High heritability coupled with high genetic advance as per cent of mean were recorded for gelatinization temperature, harvest index, total number of productive tillers per plant, number of grains per panicle, kernel length, kernel L/B ratio and grain yield per plant in case of parents and for gelatinization temperature, amylose content, total number of productive tillers per plant, number of grains per panicle and harvest index in case of hybrids indicating the additive gene effects in the genetic control of these traits and can be improved by simple selection in the present breeding material.