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Background: Cluster bean commonly known as guar is an important leguminous crop. It is widely exploited as an industrial crop because of its seeds which contain galactomannan rich endosperm. Nutrient rich green pods are used as vegetable for human consumption and plants as fodder for livestock. It is a drought tolerant hardy vegetable, which fixes atmospheric nitrogen. Even though it has great potential as a vegetable and industrial crop, it is not very popular in Kerala. So, there is a need for improvement and development of varieties suitable for climatic condition prevailing in Kerala. Hence, evaluation of germplasm has to be conducted as a preliminary step in-order to study extend of variability available in the germplasm and to identify suitable high yielding genotypes that can be utilized in the crop improvement programme. The present study was conducted to estimate genetic variability, heritability and genetic advance for yield and yield contributing characters among the collected cluster bean genotypes. Methods: Thirty accessions of cluster bean were evaluated during 2018. The experiment was laid out in randomized block design with two replications. Statistical analysis was employed for estimation of various genetic parameters such as GCV, PCV, heritability and GAM. Result: The genotypes exhibited wide variability for all the characters studied. High estimates of GCV and PCV were observed for number of branches, number of pod clusters/plant, number of pods/plant, number of pods/cluster, pod weight and pod yield/plant. High heritability coupled with high genetic advance as per cent of mean was observed for plant height, number of branches, number of pod clusters/plant, number of pods/plant, number of pods/cluster, pod weight and pod yield/plant which suggested the presence of addictive gene effects. Hence, pod yield in cluster bean could be improved through direct selection.

The study based on the characterization of natural variability of rambutan existing in the homesteads of entire Kerala state was taken up with the prime objective of comparing the Kerala collections of rambutan and rating it with the existing quality standards and popular varieties in order to develop a selection criteria. The characterization of over 100 variable types of rambutan revealed that Kerala collections of rambutan are not only comparable with the prevailing standards/varieties, but even excelled over them in most important fruit characters. Clustering of rambutan collections identified under different categories namely as elite dessert types, export types and for industrial use confirmed the superiority of six collections over others. The lowest, mid and highest values of these collections were taken for redefining the existing standards so as to categorize them as elite, super elite and an ideotype respectively. This selection criteria realized from the highest potential realized from this study can certainly serve as a directional principle to the fruit breeders that what should be an ideotype, super elite and elite and also to have a benchmark for each attribute to qualify to these standards.

Background: Climate change is a major challenge faced by the agricultural sector all over the world. Different adaptation and mitigation strategies are used to cope with these weather aberrations. Growing climate resilient crops and cultivars suitable for different regions is one of the adaptation strategy. Leguminous crops are well known for their resilience, adaptation and tolerance to adverse conditions, among these crops cluster bean is a hardy and drought tolerant crop extremely suitable for warm tropical regions. Hence identification and improvement of selected genotypes of cluster bean have paramount importance for combating the challenges possessed by the changing climatic scenario. Methods: Thirty accessions of cluster bean were evaluated during 2018. The experiment was laid out in randomized block design with two replications. Statistical analysis was employed for estimation of correlation and path coefficients. Result: The correlation analysis revealed that pod yield/plant had positive significant correlation with number of branches, number of pod clusters/plant, number of pods/plant and days to first harvest hence, selection of accessions having higher mean values for these traits could improve yield in cluster bean. Path analysis revealed that number of pods/plant had maximum positive direct effect on pod yield/plant followed by number of branches and plant height. Thus, while attempting selection for higher pod yield in cluster bean, number of pods per plant, number of branches and plant height have to be taken into account.

Thirty cluster bean genotypes collected from NBPGR Regional Station, Jodhpur was assessed to estimate the genetic divergence using Mahalanobis D2 analysis. The genotypes exhibited wide variability for all the characters studied. Thirty genotypes were grouped into V clusters. Cluster I consisted the maximum number of genotypes (12) followed by cluster II with 10 and cluster IV with 6 genotypes. Cluster III and V had only one genotype each. Intra cluster distance was maximum in cluster I with 12 genotypes indicating the high intra cluster diversity and inter cluster distance was highest between cluster V and cluster III (D2=174782.9) followed by cluster II and V (D2=115239.7), cluster III and IV (D2=78577.82), cluster I and V (D2 = 69202.2), cluster II and IV (D2 =41433.2). Mean number of branches, number of pod clusters/plant, number of pods/plant and pod yield/plant was highest for cluster V. Pod length, pod girth and pod weight were maximum in cluster III. Cluster IV and I was earliest to attain 50% flowering, days to first fruit set. Cluster III and II took minimum days for first harvest. Traits that contributed to divergence were pod yield/plant, days to 50% flowering and days to first fruit set. Hence while designing a crop improvement programme, parents for hybridization may be selected based on the inter cluster distance, mean performance of different traits and contribution of traits to divergence.