Evaluation of Brassicaceous Wild Relatives for Resistance to the Large White Butterfly, Pieris brassicae L.

Pieris brassicae (L.), a brassica specialist, is one of the most destructive and widespread pests of cruciferous crops in many countries of the world. It causes about 40 per cent damage on cruciferous crops including cabbage and cauliflower which are the two major vegetables produced and consumed in India. Development of an insect resistant cultivar is a sought after goal in insect-pest management as it provides farmers with an effective, economically sound, and environment friendly option for pest management. However, the first step in the development of an insect resistant cultivar is precise knowledge of source(s) of resistance. In this study, we screened a diverse array of 63 brassicaceous accessions (mostly wild crucifers) under field as well as laboratory conditions to determine P. brassicae performance under free choice (in the field) and no choice (in laboratory) conditions. Resistant accessions were identified among Brassica barrelieri, B. fruticulosa, B. maurorum, Crambe abyssinica, Diplotaxis muralis, D. tenuisiliqua, Erucastrum abyssinicum, Raphanus rugosum, Sinapis alba and S. arvensis. Biochemical analysis of the putative accessions revealed that high concentration of total glucosinolates had a significant negative impact on insect development, while reverse was true for total phenols and total flavonols. Our findings may be useful for genetic improvement of both vegetable and crop brassicas aimed at development of cultivars resistant to P. brassicae. This research again shows the importance of crop wild relatives for finding pest resistance.