甜荞资源萌发期耐旱性鉴定体系建立与种质筛选

Establishment of buckwheat drought tolerance identification system at germination stage and screening of drought-tolerance germplasms

为了探索荞麦萌发期耐旱性鉴定胁迫浓度与鉴定指标,建立甜荞萌发期耐旱性鉴定体系,筛选优异种质资源,以80份不同来源的甜荞种质资源为材料,通过设置不同的PEG6000胁迫浓度(10%、20%、25%和30%),研究了不同干旱胁迫对甜荞种子萌发和生长的影响。结果表明:低浓度胁迫(10%PEG6000)对甜荞种子的萌发率和根的生长影响较小,萌发抗旱指数变幅为80.92%~109.31%,对部分品种具有一定的促进作用;随着PEG6000高渗溶液浓度的升高,种子萌发率、萌发抗旱指数、株高和根长等各项指标呈下降趋势,20%PEG6000溶液胁迫下,萌发抗旱指数为50.82%~101.62%,在25%PEG6000溶液胁迫下各品种的萌发抗旱指数均在50%以下,当浓度达到30%时,萌发抗旱指数均在5%以下,显著抑制了种子的萌发,20%PEG6000溶液为荞麦萌发期耐旱性鉴定的适宜浓度;种子的相对发芽率、萌发抗旱指数、相对根长指数和根长胁迫指数4个指标与甜荞耐旱性等显著相关,相关系数分别为-0.92、-0.94、-0.85和0.85,可作为甜荞萌发期耐旱性鉴定的有效指标;通过对80份甜荞种质资源进行耐旱性鉴定,共筛选到耐旱性极强的种质资源3份(3.75%),耐旱型种质13份(16.25%),耐旱性较弱种质33份(41.25%),敏感型种质31份(38.75%)。

In order to explore the suitable stress concentration and index for the identification of the drought tolerance of common buckwheat and establish a buckwheat drought tolerance identification system at germination stage,and screening of drought-tolerance common buckwheat germplasm resources,varying concentration of polyethylene glycol(PEG)6000(10%,20%,25%,and 30%)were used for analysis of the effects of different drought stress levels on the seed germination and growth of common buckwheat.Eighty common buckwheat accessions from different regions were subjected for drought tolerance tests upon drought stress treatment.The results showed that the low concentration stress(10%PEG6000)lightly affected the seed germination and the growth of root,and the sprout index of drought resisting(SIDR)ranged from 80.92%to 109.31%.The relative germination rate,SIDR,plant height,and root length were significantly reduced with increasing concentration of PEG6000.Under the stress of 20%PEG6000 solution,the SIDR was between 50.82%and 101.62%,and under the stress of 25%PEG6000 and 30%PEG6000 solution,the SIDR of all varieties was below 50%and 5%,respectively,which significantly inhibited the seed germination.Therefore,20%PEG6000 was considered as the optimal concentration for common buckwheat drought tolerance identification.The significant correlations on drought tolerant coefficient were observed between sprout index of drought resisting,relative germination rate,relative root length index,and root length stress index.These four indices were recommended for drought resistance evaluation in common buckwheat.The 80 common buckwheat germplasm materials were classified into four groups,composing of 3 germplasm materials with high tolerance(3.75%),13 with tolerance(16.25%),33 with moderate tolerance(41.25%),and 31 with susceptibility(38.75%).