Abstract The major limiting factor in the production of pears in the tropics are the reduced number of pears cultivars adapted and the lack of knowledge of potential pollinisers among the existing cultivars. The pear tree has gametophytic incompatibility requiring a polliniser cultivar. For commercial pear tree growing, in addition to flowering synchrony and gametophytic compatibility, the metaxenia effect, which influences fruit quality, should also be considered when choosing the polliniser cultivar. This study was conducted to estimate the general combining ability (GCA) and specific combining ability (SCA) in diallel crosses to assist in the selection of pollinisers for hybrid pear tree cultivars (Pyrus communis x Pyrus pyrifolia) adapted to the low chill areas. Self-pollinations and cross-pollinations among four pear cultivars (Cascatense, Centenaria, D'agua, and Primorosa) were carried out in two seasons. The variables fruit set percentage, viable seed percentage, fruit mass, fruit length, fruit diameter, °Brix, and pH were evaluated. Afterward, a diallel analysis was performed, following the Griffing method 1, model 1, to estimate the GCA, SCA, and RE from the parents, F1 hybrids, and reciprocal F1 hybrids obtained in the crosses. The results revealed that Centenaria showed a positive additive effect for the variables studied. The cross Primorosa x Centenaria showed a high positive effect for all the evaluated traits. These results suggest the existence of a polliniser effect of the hybrid pears cultivars for the characteristics studied. This study presents information of significant value for growers interested in planting pears trees in the tropics and those involved in pears tree breeding.

中文翻译：

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杂交梨树授粉品种选择中的一般和特异配合力（Pyrus community x P. pyrifolia）

摘要 热带地区梨生产的主要限制因素是适应的梨品种数量减少以及对现有品种中潜在授粉媒介的了解不足。梨树具有配子体不相容性，需要授粉栽培品种。对于商业梨树生长，除了花期同步性和配子体相容性外，在选择授粉品种时还应考虑影响果实品质的后生效应。本研究旨在评估二列杂交的一般配合力 (GCA) 和特定配合力 (SCA)，以帮助选择适合低寒地区的杂交梨树品种 (Pyrus community x Pyrus pyrifolia) 的授粉剂。四个梨品种之间的自花授粉和异花授粉（Cascatense，Centenaria、D'agua 和 Primorosa）分两个季节进行。评估了变量坐果百分比、活种子百分比、果实质量、果实长度、果实直径、°Brix 和 pH 值。然后，按照 Griffing 方法 1，模型 1 进行双列分析，以估计来自杂交中获得的亲本、F1 杂种和互惠 F1 杂种的 GCA、SCA 和 RE。结果表明，Centenaria 对所研究的变量显示出积极的累加效应。Primorosa x Centenaria 的杂交对所有评估的性状都显示出高度的积极影响。这些结果表明杂交梨品种对所研究的特性存在授粉效应。