小麦光温敏核雄性不育系开颖和柱头外露特征及其对异交结实能力的影响

为明确小麦光温敏核雄性不育系的开颖、柱头外露特征及其异交结实能力，在小区制种条件下考察了4个不育系的开颖、柱头外露小花数和异交结实粒数，并分析了开颖率、柱头外露率与异交结实率的关系。结果表明，供试不育系的开颖率为18.10%~86.28%、柱头外露率为28.68%~67.33%，其中BS366为高开颖率低柱头外露率类型，BS206为中开颖率高柱头外露率类型，BS212为低开颖率中柱头外露率类型，BS1453为低开颖率低柱头外露率类型。供试不育系柱头外露小花和开颖小花的异交结实率分别为 59.39%~65.62%和26.16%~55.54%，二者平均异交结实率相差23.46个百分点，表明柱头外露小花异交结实能力高于开颖小花，且不育系间的差异较小。供试不育系的异交结实率在23.58%~53.16%之间，各不育系间差异显著；开颖小花异交结实粒数占总异交结实粒数的平均比例为50.55%，柱头外露小花异交结实粒数占总异交结实粒数的平均比例为68.47%。开颖率、柱头外露率与异交结实率呈极显著正相关，相关系数分别为0.719和0.372，开颖率与柱头外露率也呈极显著正相关(r=0.467)。因此，高开颖率或高柱头外露率的不育系均可获得较高的异交结实率，但柱头外露率较高的不育系异交结实率也较为稳定。在育种实践中，应首先注重选择不育系的开颖率，其次加强柱头外露性状选择，以便有效而稳定地提高异交结实率。

Characteristics of Glume Opening and Stigma Exsertion and Their Effects on Outcrossing Seed Setting Rate in Photo-Thermo-Sensitive Genic Male Sterile Lines of Wheat

In order to clarify the outcrossing seed setting ability of photo-thermo-sensitive genic male sterile lines(PTGMS) of wheat with different glume opening and stigma exsertion characteristics,the number of glume opening,stigma exsertion florets,and outcrossing seeds of four tested male sterile lines were investigated under the conditions of seed production plot in the field,and the relationships between glume opening rate,stigma exsertion rate and outcrossing seed setting rate were analyzed. The results showed that the glume opening rate of the tested male sterile lines were 18.10%- 86.28%,and the stigma exsertion rate were 28.68%-67.33%.Each male sterile line had its own characteristics of glume opening and stigma exsertion,in which BS366 exhibited high glume opening rate and low stigma exsertion rate; BS206 exhibited medium glume opening rate and high stigma exsertion rate; BS212 exhibited low glume opening rate and middle stigma exsertion rate,and BS1453 exhibited low glume opening rate and low stigma exsertion rate. The outcrossing seed setting rate of stigma exsertion florets was 59.39%-65.62%,and that of glume opening florets was 26.16%- 55.54%,with the average difference of 23.46 percentage points,which indicated that the outcrossing seed setting ability of stigma exsertion florets was higher than that of glume opening florets,and little difference existed among different male sterile lines.The outcrossing seed setting rate of the tested material was 23.58%- 53.16%,and there was significant difference among the male sterile lines. The average proportion of grain number of glume opening florets and stigma exsertion florets in total number of outcrossing seeds setting were 50.55% and 68.47%,respectively. Significantly positive correlation existed between glume opening rate,stigma exsertion rate and outcrossing seed setting rate,with the correlation coefficients of 0.719 and 0.372,respectively. There was a significantly positive correlation between glume opening rate and stigma exsertion rate(r=0.467).The male sterile lines with high glume opening rate or high stigma exsertion rate can obtain higher outcrossing seed setting rate,and the outcrossing seed setting rate of the male sterile lines with high stigma exsertion rate is more stable.In breeding practice,we should first pay attention to the selection of glume opening rate of male sterile lines,and then strengthen the selection of stigma exsertion characters,so as to improve the outcrossing seed setting rate effectively and stably.