Journal of AgriSearch 5(4):230-235 DEEP SHIKHA, ASHISH NARAYAN*, NILANJAYA, RS SINGH AND RABINDRA PRASAD ISSN : 2348-8808 (Print), 2348-8867 (Online) https://doi.org/10.21921/jas.5.4.3 AICRP on Tuber Crops, Department of Plant Breeding and Genetics, TCA, Dholi, Dr. RPCAU, Pusa, Bihar, India An Open Access International Peer Reviewed Quarterly INTRODUCTION ( The Yam bean (Pachyrhizus spp.) is one of the legume root crops. The name yam bean is used to designate the species within the genus Pachyrhizus, in particular, the three cultivated species; P. erosus, from the semiarid tropics of Central America; P. tuberosus from the tropical lowlands of both slopes of the Andean mountain range and P. ahipa from Andean highland ( ). The plant is widely cultivated in most southern states of Mexico. Moreover, P. erosus is cultivated in many South East Asian countries. P. erosus was introduced into India during the period between 1880 and 1890. In India, it is most commonly grown in North Bihar including eastern Uttar Pradesh and in parts of West Bengal, Assam, Orissa and Andhra Pradesh. Due to its high tuber productivity and nutritional value, this crop is gaining importance in other parts of India also and cultivated as minor tuber crops. The yam bean is mainly self-pollinating crop propagated by seed and needs to have the fertile shoots pruned repeatedly during the growing season in order to produce a higher tuber yield. Yam bean provides high tuber yields (Grüneberg, pers. comm.) and as a legume, it produces protein-rich food and improves sustainability in cropping systems. The starch is of good quality in regard to the digestibility and consists essentially of amylopectin ). The mature seeds of the yam bean are not used due to the high rotenone content (about 0.5% to 1% seed weight), even so, the seeds are an interesting source of high palmitic acid oil ( ). The species is found in the area with rainfall ranges from 250-500 mm to over 1500 mm. The optimal Sorensen et al., 1996 Bergthaller et al., 2001 Santos et al., 1996 ABSTRACT Altogether, 30 germplasm of Yam bean including two released varieties viz., Rajendra Misrikand- 1(RM-1) and Rajendra Misrikand-2 (RM-2) were analyzed for genetic divergence among twelve studied characters. Analysis of variance revealed highly significant differences among the genotypes for all the twelve characters under study. The (PCV) was greater than the genotypic coefficient of variance (GCV) for all the characters and high magnitude of PCV and GCV were observed for traits like tuber weight followed by tuber yield indicating that these traits could be used for tuber yield improvement but wide difference between GCV and PCV were recorded for most of the traits except for the tuber yield and tuber weight. All the thirty genotypes were grouped 2 into 6 clusters using D statistics. Highest inter-cluster distance was observed between cluster I and III (107.53) followed by cluster III and VI (97.61) and cluster I and II (78.54) on the basis of their genetic distances. Tuber yield followed by tuber weight and seed yield were having a maximum contribution towards total divergence. 2 Keywords : Yam bean, Germplasm, Genetic divergence, D statistics, clustering phenotypic coefficient of variance. ARTICLE INFO Received on Accepted on Published online 19.08.2018 12.12.2018 15.12.2018 : : : day/night temperature is 30/20°C with well-drained, sandy, alluvial soils are preferred in cultivation. MATERIALS AND METHODS An experiment was conducted to assess the genetic variability and divergence among 30 germplasm accessions of Yam bean having different geographical origin, obtained from germplasm collections maintained at Tirhut College of Agriculture, Dholi, including Rajendra Misrikand-1 (RM-1) and Rajendra Misrikand-2 (RM-2) released from All India Coordinated Research Project on Tuber Crops (AICRPTC), Dholi. The experiment was conducted in Randomized Block Design in three replications at T.C.A., Dholi Research Farm of Dr. R.P.C.A.U., Pusa, Samastipur, Bihar. Data were collected for twelve characters viz., Plant height (cm), No. of branches per plant, Days to 50% flowering, Pods per plant, Pod weight per plant (g), Pods per peduncle, Pod length (cm), No. of seeds per pod, Tuber weight (g), Dry matter (%), Tuber yield (kg/plot) and Seed yield (kg/plot). The soil of experimental site is sandy loam, basic in reaction (pH - 8.1) with available N (233.6 kg/ha.), available P (18.0 kg/ha.) and available K (142.5 kg/ha.). Weather conditions during the cropping season were moderate with total rainfall received 870 mm, maximum and 0 0 minimum temperature ranged from 30-38 C and 22-26 C, respectively and relative humidity was ranging from 50 to 98 -1 %. The crop was supplied 80:60:80 kg of NPK ha as per recommended doses. Standard cultural practices were applied during the crop period. Data for twelve quantitative characteristics were statistically analyzed for genetic variability parameters as per the standard methods. Genetic divergence analysis was performed as per ( ) and clustering of genotypes was done by using Tocher's method ( ). Mahalanobis 1936 Rao, 1952 *Corresponding Author Email : narayanashish@rediffmail.com Genetic divergence in Yam bean Germplasm