ABSTRACT Erwinia amylovora: Burrill. is the most important disease affecting quince cultivation and breeding of resistant varieties is seen as the key solution. As a result of hybridizations, 223 hybrids were obtained from 9 different combinations and susceptibility indexes (SI) of these hybrids were determined by artificial inoculations. Among the tested seven parental cultivars, Ege 25, Altın 35, Zeybek 35, and Ayva B-35 were found fire blight resistant while others were detected as moderately susceptible. SI of hybrids were changed between 14.77 and 52.94% regardless of hybrid combinations and 77.60% of obtained hybrids took place in resistant (10.1–30%) group. Reciprocal combinations showed that using resistant cultivar as a male parent was more effective than using maternal parent for transferring resistance. Heterosis (Ht) rates between combinations were found significant (p < .0004), while heterobeltiosis (Hbt) were not (p < .0623). Ht and Hbt ranged between −2.82–13.54 and −4.20–6.72 in populations, respectively. The maximum and significant heterotic effect was observed in Quince A × Ayva B-35 and its’ reciprocal combination. In moderately susceptible × resistance combination, 83.33% of F1 were determined to be resistant. On the other hand, hybrids from resistance × resistance combination were distributed in three groups as resistant, moderately susceptible and susceptible. According to these results, it could be said that (1) fire blight resistance genes in quince are recessive, (2) use of resistant varieties as pollinators is more successful in transferring resistance to hybrids, (3) open pollination treatment is an essential and easy way in terms of obtaining resistant hybrids if the orchard has resistant pollinator, and (4) heterobeltiosis for fire blight resistance is important.

中文翻译：

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抗火疫病杂交育种技术在Cydonia Oblonga上的应用：敏感性、杂种优势和杂种优势参数的基础研究

摘要 梨火疫病菌：伯里尔。是影响木瓜栽培的最重要的病害，抗病品种的育种被视为解决的关键。杂交的结果是，从 9 个不同的组合中获得了 223 个杂种，并通过人工接种确定了这些杂种的敏感性指数 (SI)。在测试的 7 个亲本栽培品种中，Ege 25、Altın 35、Zeybek 35 和 Ayva B-35 被发现具有抗火疫病性，而其他品种被检测为中度易感。无论杂种组合如何，杂种的 SI 都在 14.77 和 52.94% 之间变化，77.60% 的杂种发生在抗性（10.1-30%）组。互惠组合表明，使用抗性品种作为父本比使用母本更有效地转移抗性。发现组合之间的杂种优势 (Ht) 率显着 (p < .0004)，而异种优势 (Hbt) 则不显着 (p < .0623)。Ht 和 Hbt 在人群中分别介于 -2.82-13.54 和 -4.20-6.72 之间。在 Quince A × Ayva B-35 及其互惠组合中观察到最大和显着的杂种优势效应。在中度敏感×抗性组合中，83.33% 的 F1 被确定为抗性。另一方面，来自抗性×抗性组合的杂种分布在三个组中，即抗性、中度敏感和敏感。根据这些结果，可以说（1）木瓜中的抗火疫病基因是隐性的，（2）使用抗性品种作为传粉媒介可以更成功地将抗性转移到杂交种，