综合形态与叶片叶绿素含量的番茄壮苗指数筛选

为建立最佳的番茄秧苗壮苗指数,提高秧苗评判的准确度,该文以四叶一心番茄秧苗为研究对象,在测定11项秧苗指标的基础上,利用模糊综合评判法建立番茄秧苗综合评价指数,使用主成分分析进行指标筛选并组合构成多个番茄壮苗指数,通过综合评价指数与壮苗指数的相关分析筛选出适宜的壮苗指数并验证。结果表明:对300株样本进行统计分析,番茄秧苗综合评价指数为0.26～0.79,可全面概括秧苗的整体素质,能客观、准确地评价秧苗健壮程度;通过秧苗单一指标的主成分分析将各指标划分为形态指标、色素指标和株高3个主成分,表明秧苗的质量必须从形态、叶绿素含量和株高这3方面进行评价。从主成分中各选一种指标进行完全随机排列组合成25种壮苗指数,并筛选出与综合评价指数相关性较高且具有代表性的4种壮苗指数;并用3种不同品种番茄秧苗对其进行稳定性验证,其中壮苗指数"(总叶绿素/株高)?全株干质量"与综合评价指数相关性最大为0.797且极显著(P0.01),稳定性好、代表性强,可作为衡量番茄秧苗素质的推荐壮苗指数。以番茄秧苗的综合评价指数为分级依据,根据推荐壮苗指数将秧苗质量分为3个等级(等级Ⅰ(壮苗指数≥0.065)为优质苗,等级Ⅱ(壮苗指数:0.030～0.065)为合格苗,等级Ⅲ(壮苗指数≤0.030)为弱苗(幼苗或老苗)),各等级间差异显著,可以作为较好的判别指标。该研究表明可为番茄育苗生产提供参考,也可为其他蔬菜秧苗评判提供参考。

Selection of tomato seedling index based on comprehensive morphology and leaf chlorophyll content

Abstract: In this study, we aimed to establish an optimal index model of tomato seedlings to improve the accuracy of seedlings evaluation. Based on the determination of eleven individual indicators such as plant height, stem circumference, root-shoot ratio (Fresh), plant fresh weight, root-shoot ratio (Dry), plant dry weight, chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and SPAD of about 300 tomato seedlings with three leaves, according to the seedling standard, the membership function formula of each index was established and the single factor evaluation matrix was calculated. The weight coefficient matrix was calculated according to multiple linear regression. Finally, the fuzzy comprehensive evaluation method was used to multiply the single factor evaluation matrix and the weight coefficient matrix to calculate the comprehensive evaluation matrix and establish a comprehensive evaluation index of tomato seedlings. This index can stably and accurately evaluate tomato seedlings, but the calculation was relatively complicated. Therefore, a simple and effective seedling model was needed instead of the comprehensive evaluation index. Then the principal component analysis was used to screen the indicators and combine them into index model of tomato seedlings. After that, the suitable model was selected through the correlation analysis between the comprehensive evaluation index and seedling index model. Finally, the optimal model was selected based on the verification of suitable model using industrialized nursery seedlings of three different tomato varieties. The results showed that the weight coefficients of each indicator such as plant height, stem circumference, root-shoot ratio (Fresh), plant fresh weight, root-shoot ratio (Dry), plant dry weight, chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and SPAD of tomato seedlings were 0.180, 0.085, 0.098, 0.076, 0.103, 0.078, 0.070, 0.070, 0.070, 0.072, and 0.097, respectively. And the index was divided into three subordinate functions: parabola, positive S and straight line. The parabola included plant height, the positive S included stem circumference, plant fresh weight and plant dry weight, and the straight line included root-shoot ratio (Fresh), root-shoot ratio (Dry), chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and SPAD. The comprehensive evaluation index of tomato seedlings was calculated to be 0.26-0.79, which could comprehensively summarize the overall quality of seedlings as well as objectively and accurately evaluate the robustness degree of seedlings. The eleven individual indicators of seedlings could be divided into three principal components, including morphological indicators, pigment indicators and plant height. The morphological indicators included stem circumference, root-shoot ratio (Fresh), plant fresh weight, root-shoot ratio (Dry) and plant dry weight. The pigment indicators included chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and SPAD. Plant height was divided into one component. Twenty-five seedlings index models were combined using one indicator from each principal component and taking (stem circumference/plant height) × whole plant dry weight and (stem circumference/plant height + root dry weight/dry weight of the ground) × whole plant dry weight as the control group, furthermore, four suitable models such as (chlorophyll a/plant height) × whole plant dry weight, (total chlorophyll / plant height) × whole plant dry weight, (carotenoid/plant height) × whole plant dry weight and (SPAD/plant height) × whole plant dry weight were selected due to the high correlation and representativeness. According to the model verification results of three different tomato varieties, (chlorophyll a / plant height) × whole plant dry weight and (total chlorophyll/plant height) × whole plant dry weight were identified as the optimal models to evaluate the quality of tomato seedlings because of high correlation with the comprehensive evaluation index, good stability and representativeness. This result showed that the fuzzy comprehensive evaluation was good for assessment of tomato seedlings. According to the comprehensive evaluation index and cluster analysis of the selected seedling index model of tomato seedlings, the quality of tomato seedlings was divided into three grades, and the range of seedling index of different grades was given. The research can provide theoretical basis for tomato seedling production and also provide an optimized reference for evaluating quality of other vegetable seedlings.