Creation and evaluation of new materials for cytoplasmic male sterile lineand restorerline in upland cotton

• 1、Hebei Agricultural University/North China Key Laboratory for Crop Germplasm Resources of Education Ministry, Baoding, 071001, China

Abstract：Cotton is an important cash crop worldwide. Utilization of heterosis is an important way to improve cotton yield and quality. To solve the key problem of narrow genetic basis of parents in cotton heterosis utilization, the cotton materials 851A and ZB79185R carrying sterile genes and restorer genes respectively were used as donor parents, and cotton backbone parents Nongda 372 and Nongda 20 were used as recipient parents to create new materials of sterile line and restorer line. For developing new sterile line, the 851A served as the female for the initial cross while Nongda372, showing good genetic background, was used as male parent. This cross produced F1 progeny. For backcrossing, ‘Nongda372’ was used as the recurrent paternal parent to generate six successive backcross populations. For each generation, only plants with abortive stamens and relatively better agronomic traits were selected as maternal parents for further backcrossing. For developing new restorer line, the ZB79185R served as the female for the initial cross while Nongda20, showing good genetic background, was used as male parent. This cross produced F1 progeny. For backcrossing, ‘Nongda20’ was used as the recurrent paternal parent to generate six successive backcross populations. For the advanced backcross population, only plants with SSR markers that associated with restorer gene as well as relatively better agronomic traits were selected as maternal parents for further backcrossing. At last BC6F1 generation was self-cross to develop BC6F2, and the seedlings with strong pollen vitality and best fertility were selected as new restorer line. In this study, the new sterile line and restorer line with good genetic background were created, which will broaden the genetic basis for the utilization of heterosis and lay a material foundation for the developing strong heterosis hybrids.

Keywords： Upland cotton Cytoplasmic male sterial line restorer lines Marker assisted selection