Inheritance studies of plant height, pod and seed attributes in F2 genertion of certain groundnut (arachis hypogaea l.) crosses.

Inheritance of plant height, pod length, pod width, seed length and seed width was studied in a set of crosses grown during rabi 2007-08. F2 phenotypic data for plant height was a good fit to a phenotypic ratio of 1:4:6:4:1 and 1:2:1 respectively in two crosses studied indicating the involvement of more than two genes. Segregation of pod length in F2 generation of the cross ICGV 00350 x K 1340, was a good fit to a phenotypic ratio of 45 medium short : 19 long pods while in the cross ICGV 00350 x TG 37A segregation of pod length was a good fit to a phenotypic ratio of 1 long : 2 medium : 1 short pod length. Segregation of pod width in the crosses ICGV 00350 x K 1340 and ICGV 00350 x TG 37A presented a good fit to a phenotypic ratio of 3 high width: 1 medium width pods, while in the cross ICGV 00350 x Jyothi, F2 segregation data was a good fit to a phenotypic ratio of 1 high width: 2 medium width: 1 low width pods. F2 segregation of seed length in the cross ICGV 00350 x K 1340 was a good fit to a phenotypic ratio of 13 long medium: 3 short. Segregation of seed width in F2 generation of the crosses K 1340 x TCGS 888 and K 1340 x Narayani was a good fit to a phenotypic ratio of 15 medium low : 1 high width and 3 low : 1 medium width seeds.

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.

Variability, heritability and genetic advances in F2 generation of 15 crosses involving bold-seeded genotypes in groundnut (arachis hypogaea l.).

Significant differences were observed among F2 population of fifteen single crosses and parents for all characters. Plant height, number of primary branches, number of secondary branches, pod yield/plant showed higher values of Genotypic Co-efficient of Variation (GCV) and Phenotypic Coefficient of Variation (PCV), heritability (broad sense) and Genetic Advance as per cent of Mean (GAM). The role of additive gene action seems to be significant in the inheritance of these traits. Thus phenotypic selection is early generations would help to make improvement in these characters. Number of mature pods and number of immature pods showed low to moderate values of GCV, PCV, heritability (broad sense) and GAM. The role of non-additive gene action seems to be significant in the inheritance of these traits. In these characters, early generation selection followed by biparental matings and selection in later generations would help to isolate lines with improvement in these traits. Shelling out-turn and sound mature kernel percentage were found to be governed by both additive and non-additive gene action.

Inhibition of Aspergillus flavus colonization and aflatoxin (AfB1) in peanut by methyleugenol.

Methyleugenol is naturally occurring substance in oils and fruits and in various foods as flavoring agent. Effect of this methyleugenol in inhibiting A. flavus colonization and aflatoxin production on peanut pods and kernels has been studied. Spray of methyleugenol (0.5%) on peanut pods and kernels checked the colonization of A. flavus and aflatoxin synthesis. This chemical can be used as both prophylactic or post infection spray on peanut pods before storage. It is the first report on the inhibition of A. flavus by methyleugenol on peanut.