Kouam Eric Bertrand, Ngouana Cyrille Tedjou, Dountio Idriss Lontsi
Genetics, Biotechnology, Agriculture and Plant Production Research Unit, Department of Crop Sciences, Faculty of Agronomy and Agricultural Sciences, University of Dschang, Dschang, Cameroon.
BMC Plant Biol. 2025 Apr 21;25(1):494. doi: 10.1186/s12870-025-06529-3.
Avocado (Persea americana Mill.) is a tree of economic importance mostly grown for its fruit in home gardens and farms all over Cameroon. Plant germplasm resources are the basis for crop improvement. Analysis of complex traits and research on diversity on those resources is the first step leading to the exploration and creation of new plant varieties. The objective of this study was to assess the phenotypic variation of 206 avocado genotypes collected in ten villages across four altitude ranges in the Bamboutos highlands in western Cameroon.
Cross tabulation and Chi-square tests revealed differential distribution of traits variants among villages and altitude ranges. Various phenotypic features were observed among trees, pointing out the existence of several avocado races in Cameroon. For all the 46 qualitative traits, 162 phenotypic classes were detected, giving an average of 3.52 phenotypic classes per trait. The diversity index varied significantly between traits, populations and altitude ranges with a mean value of H'= 0.90 for qualitative traits and H'=1.31 for quantitative traits. The top five traits with higher diversity indices were fruit shape (H'=2.04), ripe fruit skin colour (H'=1.75), seed shape (H'=1.75), Tree shape (H'=1.74) and colour of flesh next to seed (H'=1.47). Bangang and Batcham populations were found to be more diverse. The lowest altitude range, 1100-1300 m above sea level (MASL) displayed smallest diversity when comparing altitude ranges. The partitioning of the diversity revealed more variation within population and within altitude ranges. Although this study revealed extensive variation between trees at the village and altitude range levels, no clear groupings of genotypes was identified based on geography. Dendrogram revealed that avocado trees from the same village and even from the same altitude ranges differ substantially. Altitude was negatively associated seed length, time from ripeness to deterioration and time from maturity to deterioration of fruits. Seventeen traits were significantly associated with the two main principal components of the PCA. Cluster analysis revealed four distinct clusters, associated to the existing avocado races.
The significant morphological variations combined with the high diversity observed in the avocado genotypes are likely to help in planning germplasm management, conservation, and improvement.
Not applicable.
鳄梨树（Persea americana Mill.）是一种具有重要经济价值的树种，在喀麦隆各地的家庭果园和农场中主要因其果实而种植。植物种质资源是作物改良的基础。对这些资源的复杂性状进行分析和多样性研究是探索和培育新植物品种的第一步。本研究的目的是评估在喀麦隆西部班布托斯高地四个海拔范围内的十个村庄收集的206个鳄梨基因型的表型变异。
交叉表和卡方检验揭示了性状变异在村庄和海拔范围之间的差异分布。在树木之间观察到了各种表型特征，表明喀麦隆存在几种鳄梨品种。对于所有46个质量性状，检测到162个表型类别，每个性状平均有3.52个表型类别。多样性指数在性状、种群和海拔范围之间存在显著差异，质量性状的平均值为H' = 0.90，数量性状的平均值为H' = 1.31。多样性指数较高的前五个性状是果实形状（H' = 2.04）、成熟果实果皮颜色（H' = 1.75）、种子形状（H' = 1.75）、树形（H' = 1.74）和种子旁边果肉的颜色（H' = 1.47）。发现班冈和巴查姆种群的多样性更高。在比较海拔范围时，海拔最低的范围，即海拔1100 - 1300米（masl）显示出最小的多样性。多样性的划分显示出种群内部和海拔范围内存在更多变异。尽管本研究揭示了村庄和海拔范围水平上树木之间存在广泛变异，但基于地理并未确定明显的基因型分组。树形图显示来自同一村庄甚至同一海拔范围的鳄梨树差异很大。海拔与种子长度、果实从成熟到腐烂的时间以及从成熟到腐烂的时间呈负相关。17个性状与主成分分析的两个主要主成分显著相关。聚类分析揭示了四个不同的聚类，与现有的鳄梨品种相关。
鳄梨基因型中观察到的显著形态变异和高多样性可能有助于规划种质管理、保护和改良。
不适用。
