Exploitation of wild species, Carthamus oxyacantha Bieb. for disease resistance and yield improvement in safflower (C. tinctorius L.).

Abstract

Safflower (Carthamus tinctroius L.) is an important edible oilseed crop in India. Safflower is susceptible to wilt (Fusarium oxysporum f.sp. carthami) and Alternaria leaf blight (Alternaria carthami). No stable resistance sources against these diseases are available in safflower. The wild species, Carthamus oxyacantha Bieb. was identified as source of resistance to wilt and Alternaria. In addition, C. oxyacantha possess basal branching habit and produces high number of branches/plant (50-100) whereas safflower cultivars produce 15-20 branches/plant from 35-60 cm above ground. The wilt and Alternaria susceptible variety, Nira belonging to C. tinctorius was crossed to C. oxyacantha and the F1 was backcrossed to Nira and advanced to BC1F6. Each generation was screened against wilt and Alternaria in field and lab under artificial epiphytotic conditions. All BC1F6 lines exhibited high resistance to wilt while four lines showed resistance to Alternaria over years. Among 28 wilt resistant BC1F6 lines evaluated for two years for yield, six lines possessing basal branching (10-12 cm above ground) and 58-82 branches/plant recorded 28-55% higher yield than check varieties, A1 and PBNS-12. They exhibited early maturity (127-130 days), and higher 100-seed weight (3.5-6.1g) and oil content (28%) than C. oxyacantha (days to maturity: 155 days; 100-seed weight: 0.8 g; oil: 24%). The results showed that genetic improvement of safflower for yield and diseases resistance was possible through wide hybridization.