Development and studies of a thermosensitive genic male sterility breeding system in rapeseed mustard Brassica juncea

摘要

A temperature (photoperiod) sensitive male sterile (MS) line K121S of rapeseed mustard (Brassica juncea L.) was developed from Yunnan mustard in 1999. The MS exhibited stable sterile with 100% sterility in summer sowing but fertile with 70% self-seed rate in autumn sowing at Kunming natural situation. Fertility alteration indicated that the expression of fertility was strongly affected by temperature but photoperiod; higher temperature can cause male sterility and lower temperature male fertility.The daily average temperature (DAT) of 3-5d before blooming influenced significantly fertility, it needed a critical temperature of over 10.8 C from fertility to sterility. Genetic study suggested K121Sbelongs to a thermosensifive genic male sterility (TGMS) system with fertility controlled by two pair recessive duplicated sterile genes (ms1 and ms2) which interact with a pair of recessive inhibitor gene with sensitivity to temperature (i). The inhibitor gene is active and the MS genes can be suppressed to cause the male fertile when DAT is below the critical point, but it's inactive and the MS genes can be expressed normally when DAT is above the critical value. So besides the TGMS (TypeⅢ) K121S (ms1ms1ms2ms2ii), in this system there are another two types GMS line, (TypeⅠ)116A (ms1ms1ms2ms2Ⅱ) is not sensitve to temperature and can be kept in 1:1 ratio by sister-cross of sterile plant with fertile plant with genotype ( MS1ms1ms2ms2Ⅱ) or (ms1ms1MS2ms2Ⅱ), (TypeⅡ) 1 20A(ms1ms1ms2ms2li) is also not temperature sensitive but just can be maintained by TypeⅢ under autumn sowing in Kunming situation. A full sterile population with insensitive to temperature can be obtained by Typel crossed to TypeⅢ in lower temperature situation and can be used to produce hybrid in any condition. Therefore, TGMS two-lines method and GMS three-lines method can all be used to produce hybrids based on the new system in Brassica juncea L.