Sugarcane Research Institute, Yunnan Agricultural University, Kunming, China.
Wenshan Academy of Agricultural Sciences, Wenshan, China.
Plant Biol (Stuttg). 2020 Jul;22(4):623-633. doi: 10.1111/plb.13110. Epub 2020 Apr 15.
Saccharum spontaneum L. is one of the most important germplasm resources for modern sugarcane breeding. Exploring the cold tolerance of S. spontaneum clones with different ploidy levels and screening for cold-tolerant material can be helpful in parent selection for breeding cold-tolerant sugarcane. Morphological indices, leaf ultrastructure and physiological indices were used to evaluate the cold tolerance of 36 S. spontaneum clones with different ploidy levels (2n = 40, 48, 54, 60, 64, 78, 80, 88, 92 and 96). The morphological indices of S. spontaneum clones with different ploidy levels were positively correlated with ploidy. Under low-temperature stress, the chloroplast and mitochondrial structures of the clones with high ploidy were more severely damaged than were those of clones with low ploidy. A comprehensive evaluation of the physiological indices showed that the 36 S. spontaneum clones could be divided into four categories: strongly cold tolerant, cold tolerant, moderately cold tolerant and cold sensitive. Correlation analysis of the morphological indices and cold tolerance revealed a significant negative correlation between cold tolerance and ploidy. On the basis of the morphological and physiological indices, optimal stepwise regression equations that can be used for the selection of cold-tolerant S. spontaneum resources were established. The S. spontaneum clones with low ploidy are more cold tolerant than those with high ploidy. Clones 12-37, 13-10 and 12-23 are strongly cold-tolerant germplasm resources, which suggests these germplasm sources have high potential for use in breeding cold-tolerant sugarcane.
甜根子草（Saccharum spontaneum L.）是现代甘蔗育种最重要的种质资源之一。探索不同倍性甜根子草克隆的耐寒性并筛选耐寒材料，有助于甘蔗耐寒性亲本的选择。利用形态指标、叶片超微结构和生理指标对 36 个不同倍性（2n=40、48、54、60、64、78、80、88、92 和 96）的甜根子草克隆进行了耐寒性评价。不同倍性甜根子草克隆的形态指标与倍性呈正相关。在低温胁迫下，高倍性克隆的叶绿体和线粒体结构比低倍性克隆受损更严重。生理指标综合评价表明，36 个甜根子草克隆可分为四类：强耐寒型、耐寒型、中度耐寒型和敏感型。形态指标与耐寒性的相关分析表明，耐寒性与倍性呈显著负相关。基于形态和生理指标，建立了可用于筛选耐寒甜根子草资源的最优逐步回归方程。低倍性甜根子草比高倍性甜根子草更耐寒。12-37、13-10 和 12-23 号克隆为强耐寒种质资源，这表明这些种质资源在培育耐寒甘蔗方面具有很高的应用潜力。
