苦瓜核心种质资源构建方法的比较

摘要

Objective] To construct core collections of bitter gourd ( Momordica charantia ) which can represent the genetic diversity of the initial population by comparing different construction methods, and facilitate the efficient utilization of bitter gourd germplasm. [Method]We sampled 154 bitter gourd germplasm as materials, predicted the genotypic values of five traits ( node bearing first female flower, fruit length, fruit width, flesh thickness and mass per fruit ) without bias using mixed linear model analysis, calculated the genetic distances among bitter gourd germplasm based on genotypic values of all five traits using Mahalanobis distance, and constructed core collections with 30% sampling proportion by using eight different clustering methods and three different sampling strategies. The quality of core collections constructed using different clustering methods and sampling strategies were evaluated.[Result] The variation coefficients of all five traits of the core collections constructed with eight clustering methods were larger than those of the initial population. Single linkage was better compared to the other seven clustering methods by significantly increasing the variances and coefficients of variation for all five traits. The ranges of core collections constructed with preferred sampling and deviation sampling were consistent with those of the initial population. The variation coefficients of three traits of the core collection from deviation sampling were larger compared to the other two sampling methods, indicating that deviation sampling was slightly better than random sampling and preferred sampling. Forty six core collections of bitter gourd were obtained based on Mahalanobis distance, deviation sampling and single linkage. Among them, Y5, Y87, Y112 and Y139 were the backbone materials. [Conclusion]The 46 core collections of bitter gourd, which were obtained based on Mahalanobis distance, deviation sampling and single linkage, can well represent the genetic diversity of the initial population. This study further provides evidence for high genetic diversity in the bitter gourd germplasm from India and Southeast Asian. Our results provide an important theoretical basis for the collection, evaluation and efficient utilization of bitter gourd genetic resources.%【目的】通过比较不同方法构建的苦瓜Momordica charantia核心种质资源的优劣,选择能代表原群体遗传多样性的核心种质,为苦瓜种质资源的高效利用提供依据。【方法】采用混合线性模型对154份苦瓜种质的第1雌花节位、瓜纵径、瓜橫径、瓜肉厚和单瓜质量等5个性状的基因型值进行无偏预测；基于性状的基因型预测值,采用马氏距离计算苦瓜种质间的遗传距离；通过8种聚类方法和3种抽样方法,按照30%的抽样率构建苦瓜核心种质资源,评价不同聚类方法和抽样方法构建苦瓜核心种质的优劣。【结果】8种聚类方法构建的核心种质所有5个性状的变异系数均高于原群体；最短距离法构建的苦瓜核心种质5个性状的方差和变异系数均高于原群体,明显优于其他7种聚类方法。优先抽样法和偏离度抽样法构建的核心种质的极差与原群体一致,但偏离度抽样法构建的苦瓜核心种质有3个性状的变异系数高于其他2种抽样法,表明偏离度抽样法略优于随机抽样法和优先抽样法；基于马氏距离、偏离度抽样法及最短距离法获得了46份苦瓜核心种质,其中,Y5、Y87、Y112和Y139为苦瓜骨干材料。【结论】基于马氏距离、偏离度抽样法及最短距离法获取的46份苦瓜核心资源能够代表原群体的遗传多样性。本研究进一步证实了来源于印度及东南亚地区的苦瓜种质具有丰富的遗传多样性,为苦瓜种质资源的收集、评价与高效利用提供了重要依据。