Reaction to certain disease-insect complexes of the breeding lines derived from two interspecific crosses of soybean [Glycine max (L.) Merr.]

Abstract

The soybean has been one of the most important kharif crops of Tarai and Bhabar areas of Uttar Pradesh. In Kharif 1994, a wide spread premature drying (Fungal complex) of soybean was noticed at farmers field in this area resulting in severe reduction of soybean yield. The crop was apparently normal upto flowering stage (R 1 and R2 stage) but thereafter, drying of the plants started in patches. The disease started with yellowing of foliage and wilting of the plants and finally plants dried an,d werr;l killed before maturity. The pods were few in number mostly empty or having only a few small shriveled grains. Petioles with or without leaves remained attached to the dead stem, stem had lesions on them. The root system was destroyed and charcoal rot symptom were seen on majority of plants. On isolation, in additon to Macrophomina phaseolina (Charcol rot), species of Col/etrotrichum Fusarium and Rhizoctonia were found associated with fungal complex affecting the plant. In some fields, root knot symptoms were also observed and in some other fields, nematode larvae were also seen on root system of the infected plants.