甘薯产量、品质及农艺性状的基因型与环境效应研究

Genotypic variation and environmental effects on yield, quality and agronomic traits of sweet potato

  • 摘要: 选育具有优质淀粉或花青素性状的甘薯新品种是甘薯育种的重要目标。本研究利用5个白肉(薯肉颜色为白色或淡黄色)甘薯品种(系)和5个紫肉(薯肉颜色为紫色)甘薯品种(系)的自然变异, 于2012年和2013年对重庆市6个地点2年间甘薯淀粉和花青素等性状测定结果进行方差分析、变异分析和相关性分析, 以期对甘薯产量、品质和农艺性状的自然变异规律和环境影响因素进行探索。结果表明, 基因型效应和环境效应下甘薯产量性状(鲜薯产量、淀粉产量、薯干产量)和品质性状(干率、淀粉含量、花青素含量)差异均达到显著水平(P<0.05)或极显著水平(P<0.01)。供试的所有甘薯品种(系)淀粉含量的基因型效应>环境效应>年份效应, 白肉甘薯产量性状的环境效应>基因型效应>年份效应, 紫肉甘薯产量性状的环境效应、年份效应大于基因型效应。重庆中海拔地区(万州区或酉阳县)甘薯产量相对较高, 低海拔地区(合川区、北碚区)甘薯薯块熟食性较好, 并且薯块熟食适口性评分低海拔地区>中海拔地区>高海拔地区(黔江区或巫溪县)。甘薯农艺性状(茎粗、最长蔓长、基部分枝数)和产量性状平均变异系数较大(CV=0.30, 0.28), 品质性状(干率、淀粉含量、薯块熟食适口性评分)平均变异系数较小(CV=0.11), 但花青素含量平均变异系数较大(CV=0.28)。相关性分析显示, 甘薯鲜薯产量、淀粉产量、薯干产量之间均呈极显著正相关(r≥0.700); 淀粉产量、薯干产量均与淀粉含量呈极显著正相关(r≥0.363)。白肉甘薯茎粗与最长蔓长呈极显著正相关(r=0.439), 与淀粉含量呈极显著负相关(r=0.433), 与淀粉产量呈显著负相关(r=0.318)。紫肉甘薯商品薯率与基部分枝数、淀粉产量、薯干产量均呈显著正相关(r=0.345, 0.368, 0.357), 基部分枝数与最长蔓长呈显著负相关(r=0.397)。白肉甘薯和紫肉甘薯在产量、品质及农艺性状的影响因子上存在不同, 在品种选育时应针对不同甘薯类型和育种目标采取不同选育方案。本研究可为筛选有利于甘薯品质性状形成的环境因子、促进育种手段和栽培技术的改进、加快甘薯品质改良提供理论依据。

     

    Abstract: The development of new sweet potato varieties with high starch and anthocyanin contents in storage roots has been the key objective of sweet potato research. In this study, natural variations in five white-fleshed sweet potato (with white or pale yellow flesh color) varieties (lines) and five purple-fleshed sweet potato (with purple flesh color) varieties (lines) were analyzed for the effects of environments on quality traits of storage roots in 2012 and 2013. Analyses of variance and correlation were conducted for the two types of sweet potato accessions in six regions of Chongqing City. The results showed significant differences (P < 0.05) or extremely significant differences (P < 0.01) in yield-related traits (e.g., fresh yield, starch yield and dry root yield) and quality traits (e.g., starch content, dry matter content and anthocyanin content) among genotypes and environments. For all the tested sweet potato varieties (lines), genotypic effect on starch content was greater than environmental and temporal effects. For white-fleshed sweet potato accessions, environmental effect on yield-related traits was greater than genotypic and temporal effects. For purple-fleshed sweet potato, however, environmental and temporal effects on yield were greater than genotypic effect. While higher yield was obtained at intermediate altitude (i.e., Wanzhou or Youyang) conditions, better palatability was obtained at low altitude (i.e., Hechuan and Beibei) conditions. Furthermore, the grade of palatability at intermediate altitude was higher than that at high altitude (i.e., Qianjiang or Wuxi) conditions. The mean variation coefficients (CV) of morphological traits (e.g., stem diameter, vine length and breach number, CV = 0.30) and yield-related traits (CV = 0.28) were high, those of quality traits (e.g., dry matter content, starch content and palatability) was even much smaller (CV = 0.11), while that of anthocyanin content was also high (CV = 0.28). Correlation analysis suggested extremely positive correlations (r ≥ 0.700) among fresh yield, starch yield and dry root yield of sweet potato. Starch content had extremely positive correlations with dry root yield and starch yield (r ≥ 0.363). For white-fleshed sweet potato accessions, stem diameter had extremely significantly positive correlation with vine length (r = 0.439), extremely significantly negative correlation with starch content (r = 0.433), and significantly negative correlation with starch yield (r = 0.318). For purple-fleshed sweet potato accessions, commodity rate was significantly positively correlated with branch number, starch yield and dry root yield (r = 0.345, 0.368 and 0.357, respectively). In addition, a significantly negative correlation (r = 0.397) was noted between vine length and branch number. It was concluded that affecting factors of yield, quality and agronomic traits of different genotypic accessions of sweet potato were different. Individualized selection and breeding approaches should be adopted on the basis of sweet potato types and breeding targets. The results provided valuable theoretical reference for screening advantageous environmental factors for quality traits formation, improvement of breeding approaches, and cultivation techniques of sweet potato. This could facilitate the promotion of quality improvement of sweet potato.

     

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