甘蔗双腋芽突变体表型鉴定及应用潜力评估

蔗茎腋芽是甘蔗无性繁殖的主要器官,充足的下芽量保证了甘蔗的高产稳产,但同时也造成用种量大、种植成本高,是生产上一直难以平衡的问题。本研究以大茎野生种创新利用过程中获得的1份蔗茎孪生双腋芽的突变体种质云蔗07-86为材料,对其双腋芽表型、稳定性、可遗传性及对产量的影响进行鉴定和测试。研究发现该突变体的双腋芽以孪生、邻接和分离3种方式随机着生于蔗茎中上部,通常从地上第6茎节开始发生双腋芽,发生频率自下而上呈现从无到有、先增后减的总体趋势,且播种后2个腋芽均能正常萌发;通过连续多年的无性繁殖大田试验观察发现,双腋芽性状能够在繁殖群体中稳定保持;利用该突变体与32份不同的甘蔗种质进行杂交,仅在11个组合中的极少数杂交后代无性系上观察到双腋芽现象,表明双腋芽性状可以通过杂交传递给后代,但双腋芽在后代群体中出现的概率极低;以相同下芽量分别将突变体单、双腋芽种茎进行种植,发现不同腋芽表型类型的有效茎数、蔗茎产量差异不显著,表明双腋芽突变体具备保证下芽量而降低用种量的应用潜力。本研究为后期开展双腋芽形成候选基因挖掘及双腋芽突变育种利用奠定基础。

Phenotypic Identification and Evaluation of Application Potential in Double Axillary Buds Mutant of Sugarcane

The axillary bud on cane stalk is the main reproductive organ for sugarcane vegetative reproduction.To ensure enough bud setts at planting is an essential prerequisite for high and stable cane yield,but too large bud setts also mean high planting cost.This is a common dilemma in sugarcane production.In previous studies on innovative utilization of hybrid from Saccharum robustum E.W.Brandes&Jeswiet ex Grassl,one mutant with double axillary buds(YZ 07-86)was exploited.In this study,the twin axillary buds phenotypic frequency,stability,hereditability and its yield impact were determined.The double axillary buds were found to be randomly inserted from the 6 th stem node above ground to stem tip in three ways(twins,adjoined and separated),with an overall tendency of increasing first and then decreasing.Importantly,both of the double axillary buds are generally able to germinate after planting.Under a test of field-conditional asexual reproduction over years,the double axillary buds was found to be stably inherited in the population.By making crosses with 32 different sugarcane varieties,a few of progeny individuals with the double axillary buds was observed from 11 hybridization combinations.That suggested that the trait of double axillary buds was able to be transmitted by hybridization to the progeny with a very low frequency.In the yield comparison test with same amount of buds but planting single or double axillary bud setts respectively,no significant difference in millable stalks and cane yield was observed,suggesting a significant applied potential with the mutant in the sugarcane seed market.This study could establish a foundation for the following research such as the mining for candidate genes of double axillary buds and the practical use in sugarcane breeding.