Novel sources of cauliflower for resistance to downy mildew disease, genetic analysis and design suitable breeding strategy using advanced breeding lines

Cauliflower is the leading cole vegetable in India and many parts of the world. The productivity of this crop is severely affected by downy mildew disease. In the present study, advanced breeding lines including resistant and susceptible checks were phenotyped followed by genotyping was carried out using linked markers. Ten plants in each line were scored and finally Disease Index (DI) was calculated. The inheritance of resistance was carried out using chi-square (χ2) and resistant hybrids were developed using resistant advanced lines validated through linked markers. The lowest DI was recorded in advanced line DMR-2–0–7 followed by DMR-8–4–8–1. Two resistant advanced lines viz. DMR-3–0–8 and DMR-40–5–8–1 were validated by three SCAR markers (SCR15, SCJ19, UBC 359) along with the resistant check. On the basis of the cluster analysis, the advanced lines were grouped into three clusters. The dendrogram revealed significant genetic diversity among 12 advanced lines. The segregation of downy mildew susceptible and resistant plants in F2 population of DMS-27–2–1–0–3 × DMR-40–5–8–1 segregated in 114 resistant and 36 susceptible suggesting single dominant gene. Significantly high average curd weight (1483.33 g) was obtained in Hyb 7 (DMR-7–4–5–3 × DMR-40–5–8–1). The highest ascorbic acid (52.67 mg 100 g FW-1) was obtained in Hyb 5 (DMR-7–4–5–3 × DMR-8–4–8–1). We have emphasized development of end product to bridge the gap between availability of genetic resources and advanced molecular breeding. The study will be very useful to the cauliflower breeder in enhancing breeding efficiency for the farmers as well as consumers.