Genetic Divergence in Mid Early Group Genotypes of Rice (Oryza sativa L.).

Sixty four mid early group genotypes of rice were studied for genetic diversity for yield and yield contributing characters. Cluster analysis revealed sixty four genotypes were grouped into 11 clusters. The pattern of distribution of genotypes into different clusters was at random. Plant height contributed maximum towards genetic divergence followed by days to 50% flowering. The maximum inter cluster distance observed for between 4 and 7 (182.08) followed by cluster 1 and 4 (169.94). The genotypes from these clusters can be utilized in hybridization programme for improvement of rice.

Genetic Divesity and Molecular Characterization of Mungbean Genotypes (Vigna radiata (L.) Wilczek).

The present investigation was undertaken to examine the genetic divergence in 50 mungbean germplasm lines for 13 characters using Mahalanobis D2 statistics. The genotypes grouped into eight clusters. Cluster VII had maximum intra-cluster distance while inter-cluster distance was highest between clusters V and VII. Cluster means indicated that none of the clusters was superior for all the characters studied. Therefore, hybridization between genotypes belonging to different clusters is suggested for development of superior genotypes. 10 SSR primers were used for molecular study of which only one gave slight difference among 19 mungbean genotypes. The quality and quantity of DNA used for amplification by PCR is the key to reproducible results and success of genotyping. Especially, DNA purity is extremely crucial for obtaining clear and discriminate patterns. DNA extraction from mungbean is difficult due to presence of contaminants such as phenols. Therefore, the present study was under taken to obtain high quality and pure DNA in mungbean. With few modifications four different DNA extraction protocols were tried in the present study to obtain high quality and pure DNA viz., (I) Doyle and Doyle (1987), (ii) Method of Murray and Thompson (1980), (iii) Porebski et al.(1997), and (iv) Lin et al. (2001). Out of the four methods tried for DNA extraction, the method of Lin et al. (2001) was found most efficient, as the DNA obtained through this protocol was relatively pure which gave amplyfying products in the PCR. The genotype used for the standardization was MGG -361. Molecular characterization of 19 randomly chosen mungbean genotypes was attempted with the eight standardized primers. None of the primers showed scorable polymorphism. The primers VR4, VR5 and VR9, exhibited non specific bands, in addition to the monomorphic bands.