高种植密度条件下玉米杂交种耐密性鉴选指标及评价方法
为探明准确有效鉴定玉米杂交种的耐密性指标及方法,进而筛选出适宜于高密度种植的耐密高产玉米杂交种,本研究采用生产实践中种植密度8.25万株/hm2和在此基础上增加1.5万/hm2(10.5万/hm2)两个种植密度,并以28个玉米杂交种为材料,测定植株形态、物质积累、光合特性、穗部性状及单株产量等13个相关指标,利用相对值变异系数较大的指标作为杂交种耐密性强弱的鉴选和评价指标,再利用以指标归一化的变异系数作为权重的模糊隶属函数综合评价方法对28个玉米杂交种的耐密性进行评价。结果表明：以各指标相对值的变异系数(CV≥15%)为标准,筛选出相对茎粗、相对SPAD值、相对Pn、相对干物质量、相对秃尖长、相对行粒数和相对单株产量7个主要指标作为耐密性的评价指标。以7个主要指标归一化变异系数为权重对28个杂交种的耐密性进行模糊隶属函数综合评价,筛选出耐密性较强的杂交种为利民33、登海618、瑞普908、华美1号、KWS2564等,耐密性较弱的杂交种四单19、科河8号、丰田6号、陇单339等,其他杂交种为中间型,鉴选结果与生产实践吻合,并利用主成分分析法进一步验证,得出耐密性强和弱的前5个品种的重合度均为90%。因此,此评价方法可以作为评价玉米耐密性的有效方法,为准确有效评价鉴选玉米耐密性提供理论依据。
英文摘要:
In order to find out the density tolerance indexes and accurate and effective methods for determing the maize hybrid varieties, for further screening the maize hybrid varieties suitable for high density planting, this research adopts the planting density of 82500 plants/hm2, which was adopted in production practice, and 105000 plants/hm2 (an increase of 15000 plants/hm2 planting density on the basis of production practice). Plant morphology, matter accumulation, photosynthetic characteristics, panicle traits and yield of 13 related indicators, were determinated in 28 maize hybrids. Their density tolerance were evaluated using the relative variation coefficient of indicators and further using index variation coefficient of normalized as weight fuzzy, comprehensive evaluation method of membership grade function. Results show that seven major indicators: relative stem diameter, relative SPAD value, relative Pn, relative dry matter weight and relative bald tip length, relative kernel per row and relative grain yield of plant, were screen out as evaluation index for density tolerance, using the index of relative coefficient of variation (CV≥15%) as the standard. Using seven main index normalized weight coefficient of variation and fuzzy comprehensive evaluation(the membership function), the 28 hybrid varieties could be graded as 3 group: Limin33,Denghai618,Ruipu908,Huamei1 and KWS2564 etc as stronger density tolerance, Sidan 19, Kehe8, Fengtian6, Longdan339 etc as weaker density tolerance, other hybrids as middle type. The results accord with the production practice: the contact ratio for 90% in the first five strongger varieties and weaker varieties for density tolerance, which were further verified using the principal component analysis. Therefore, this evaluation method can be used as an effective method to evaluate maize density tolerance, and provide theoretical basis for accurate and efficient evaluation of density tolerance.
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