Identification of early, wilt resistant and good combining male lines of castor (Ricinus Communis L.,) suitable for rainfed conditions

Abstract

Prolonged crop duration (150-210 days) and tall plant height (>100 cm) of castor either hinders its adaptability to newer and niche areas or fitting into the cropping sequence of conventional castor growing areas. The present study aims at evaluating male lines for their agro-morphological characters, combining ability for seed yield, yield components and resistance to Fusarium wilt. Node number to primary, first and second order of secondary (P, S1 and S2) racemes were taken as indicators of flowering and maturity duration of male lines while data on plant height up to primary spike was recorded for plant stature. Twenty-six improved monoecious lines were evaluated for their agro-morphological characters in an ARBD design along with three checks replicated five times during 2017-18 kharif season. Simultaneously all the 26 lines were screened for wilt resistance in wilt sick plot in two replications. Nineteen monoecious lines were resistant to wilt (0-20% wilt incidence) while four lines were moderately resistant to wilt (20-30%). Four lines viz., ICS-121, ICS-150, ICS-127 and ICS-139 were promising with significantly low node number to P, S1 and S2 order of racemes compared to early maturing check, DCS-9 (12.1, 5.8, 4.9). Eight male lines were significantly shorter than the very tall type checks, 48-1 and DCS-107 (>85 cm) while ICS-121 (57.5 cm) was on par with the medium statured check, DCS-9 (59.7 cm). Fifteen hybrids, generated by crossing three pistillate lines and five selected wilt resistant male lines in a line x tester design were evaluated along with eight parents and two hybrid checks during 2019-20 kharif season. SKP-84 (pistillate line) and ICS-139 (male line) were identified as good combiners for seed yield and majority of the yield components.

Keywords

• monoecious
• combining ability
• gca
• sca
• castor