Evaluation of Growth and Yield Performance of Castor Hybrids Under Southern Dry Region in Sri Lanka

Castor oil is considered as a highly important industrial oil due to its unique chemical structure and properties. Although it is not yet commercially grown in Sri Lanka, there is a high potential of promoting castor cultivation in marginal lands. Due to growing interest among the private sector to initiate commercial scale cultivation, there is an immediate necessity to introduce promising castor varieties despite traditional varieties are presently grown. With this objective two castor hybrids, namely; Jiaxiang No.6 (JX-6) and Zibi No.5 (ZB5) were received from China and field evaluation was carried out at Grain Legumes and Oil Crops Research and Development Center, Angunakolapelessa (GLORDC) during 2021/22 Maha season. The experiment was layout in a Randomized Complete Block Design (RCBD) with four replicates, where a local cultivar was used as a check variety. The results revealed, plant height at flowering was not significantly different (P=0.05) among the tested genotypes. Since the local cultivar is having a perennial growth habit, significantly higher (P=0.05) branching was observed. The number of racemes per plant was significantly high (P=0.05) in the local cultivar, while average raceme length and number of fruits per raceme were significantly high (P=0.05) in both hybrids. Additionally, hybrids had higher 100 seed weight ranging from 20.82-23.1g. Hence, a significantly higher (P-0.05) seed yields has been revealed by the hybrid varieties Interestingly, both hybrids showed severe disease susceptibility specially for fusarium wilt, in which the local cultivar showed high degree of resistance. Considering the yield performance, only the hybrid of Jx-6 was selected as a promising hybrid to initiate commercial scale cultivations.