Generation and characterization of pea (<i style="">Pisum sativum</i>) somaclones for resistance to Ascochyta blight and powdery mildew

Abstract

Somaclones of two pea cultivars, Palam Priya and Lincoln were generated and evaluated for resistance to Ascochyta blight and powdery mildew. Among the hormonal combinations tested for callus induction in MS medium, the best combination observed was 2,4-D + NAA + BAP 0.5 mg/l each using leaf explants. Frequency of callus differentiation was maximum (10 and 23.5% for Palam Priya and Lincoln, respectively) on MS medium containing NAA 0.5 mg/l + BAP 6 mg/l but shoots formed withered and did not root either. However, MS medium containing NAA 0.5 mg/l + BAP 5 mg/l gave good differentiation. <i style="">In vitro</i> flowering as well as seed formation was also observed in 11 shoots. Vigorous rooting was obtained when <i style="">in vitro</i> grown shoots having node at cut end were cultured on half strength MS medium containing NAA 2 mg/l. Five of 71 Lincoln somaclones and 1 of 21 Palam Priya somaclones showed resistance to <i style="">Ascochyta pinodes</i> but none were resistant to <i style="">Erysiphe pisi</i>. However, one somaclone (SP6-1) of Palam Priya possessing resistance to Ascochyta blight also showed moderate resistance to powdery mildew. Increased PAL as well as peroxidase activity was observed in somaclones showing resistance to Ascochyta blight. Variation in the banding pattern of esterase was also observed in the native-PAGE profiles of Palam Priya and Lincoln, and somaclones derived from them.