正反交亲本配置方式对燕麦F1代杂种优势和表型的影响

Effects of reciprocal crosses on heterosis and phenotype of F1 hybrids of oats

摘要:

【目的】明确燕麦正交和反交对杂交后代杂种优势的影响及其表型差异。【方法】以陇燕 4 号和陇燕 5 号为亲本配制正反交组合，对获得的杂种后代与其亲本进行对比，分析其杂种优势，比较其表型差异。【结果】在测定的 12 项指标中，具有正向超亲优势的并不多，正交组合中，分蘖数、株高、旗叶长 、旗叶宽和倒二叶长表现出正向超亲优势，其余指标均表现出负向优势，旗叶长的超亲值最高 （23. 0%），穗下节长的超亲值最低（-10. 3%）；反交组合中，除倒二叶长、主穗粒数和千粒重的超亲优势表现为正向外，其它性状均表现出负向优势，其中旗叶长的超亲值最高（17. 4%），分蘖数的超亲值最低（-25. 0%）。正交组合中分蘖数、株高、旗叶长、旗叶宽和倒二叶长的杂种优势大于 100%，其中旗叶长的杂种优势指数最大，为 123. 5%；其次为分蘖数和倒二叶长，分别为 120. 0% 和 112. 5%，其余性状的杂种优势指数均小于 100%；反交组合中，株高、旗叶长、倒二叶长和主穗粒数、千粒重的杂种优势指数均大于 100%，其中旗叶长和主穗粒数的值最大，分别为 117. 4% 和 116. 7%，千粒重和株高的杂种优势不明显。总体而言正交的杂种优势大于反交；旗叶长在 F₂代发生了分离，正交中仅有 5% 的植株超亲优势值为负值，而反交中则为 15. 0%。F₂代分蘖数的变化呈偏正态分布，正交中超亲优势大于 0 的个体只占 43. 3%，反交的超亲优势大于 0 的只占 10. 0%。【结论】分蘖数、株高、旗叶长、倒二叶长、主穗长和主穗粒数 6 个性状受母本细胞质遗传的影响较大。

Abstract:

【Objective】 In order to clarify the effects of oat orthogonal and reverse cross on heterosis and pheno- typic differences of hybrid offspring.【Method】 In this study，Longyan No. 4 and Longyan No. 5 were used as parents to prepare reciprocal cross combinations，and the obtained hybrids were compared with their parents to analyze their heterosis and compare their phenotypic differences.【Result】 The results showed that among the 12 indexes，there were not many positive super parent advantages. In the orthogonal combination，the number of tillers，plant height， flag leaf length，flag leaf width and inverted two leaf length showed positive super parent advantages，and the other in- dexes showed negative advantages. The super parent value of flag leaf length was the highest （23. 0%） and the su- per parent value of lower panicle node length was the lowest （-10. 3%）. In the reverse cross combination，except that the super parent advantages of the length of the second leaf，the number of grains per main panicle and thousand seed weight showed positive outward，the other characters showed negative advantages，in which the super parent value of flag leaf length was the highest （17. 4%） and the super parent value of tiller number was the lowest （-25. 0%）. Based on the analysis of super parent heterosis，the heterosis index of each character was analyzed. It was found that the heterosis of tiller number，plant height，flag leaf length，flag leaf width and inverted two leaf length in the orthogonal combination was more than 100%，and the heterosis index of flag leaf length was the largest，which was 123. 5%；The second was the number of tillers and inverted two leaf length，which were 120. 0% and 112. 5% respectively. The heterosis indexes of other characters were less than 100%. In the reverse cross combinations，the heterosis indexes of plant height，flag leaf length，inverted two leaf length，grains per main panicle and thousand seed weight were more than 100%，and the values of flag leaf length and grains per main panicle were the largest，117. 4% and 116. 7% respectively. The heterosis of thousand seed weight and plant height was not obvious. In general，the heterosis of orthogonal was greater than that of backcross； In the F₂ generation，the flag leaf length was separated in the F2 generation. In the orthogonal，only 5% of the plants had negative super parent heterosis，while in the back- cross，it was 15. 0%. And there are great differences between positive and negative cross. The change of tiller num- ber in F2 generation showed a partial normal distribution. Only 43. 3% of the individuals with super parent advantage greater than 0 in orthogonality and 10. 0% of the individuals with super parent advantage greater than 0 in backcross. 【Conclusion】 The six traits of tiller number，plant height，flag leaf length，inverted two leaf length，main panicle length and grain number of main panicle were greatly affected by the cytoplasmic inheritance of female parents.