Abstract:

Bean pyralid (Lamprosema indicata Fabricius) is one of the major leaf-feeding insects for soybeans and causes serious damage in soybean production in central and southern China. The objective of the present study was mainly to reveal the inheritance of resistance to L. indicate in soybeans using three recombinant inbred line (RIL) populations derived from susceptible by resistant crosses, i.e. NJRIKY, NJRIWT and NJRISX (derived from Kefeng 1 × Nannong 1138-2, Wan 82-178 × Tongshanbopi-huangdoujia and Su 88-M21 × Xinyixiaoheidou, respectively) in the field under natural infestation. Based on the observation of symptoms damaged by the insect on soybeans, rolled leaf percentage, rolled leaf number, and seed yield were examined as resis-tance (damage) indices. Among them, the rolled leaf percentage tested in early September was the best index of resistance to L. indicata due to its higher genetic variation, heritability value and environment-stability, as well as higher negative correlation with seed yield in the three populations. Segregation analyses showed that resistance to L. indicata was dominated by two major genes plus polygenes in the three populations, with their major gene heritability of 51.0%, 80.5%, and 56.3%, and polygene heritability of 39.1%, 11.4%, and 29.1%, respectively. The major gene genotypes of the RILs of the three populations were determined and grouped according to their posterior probability, which could be utilized as reference in selection for resistance lines.

Key words: Soybean, Lamprosema indicata (Fabricius), Resistance to insects, Major-gene plus polygenes mixed inheritance model, Segregation analysis