Horgan Finbarr G, Bernal Carmencita C, Ramal Angelee F, Almazan Maria Liberty P, Mundaca Enrique A, Crisol-Martínez Eduardo
EcoLaVerna Integral Restoration Ecology, Bridestown, Kildinan, T56 P499 Co. Cork, Ireland.
Escuela de Agronomía, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule, Casilla 7-D, Curicó 3349001, Chile.
Insects. 2024 Feb 28;15(3):164. doi: 10.3390/insects15030164.
Three-line hybrid rice is produced by crossing male sterile (A line) rice with a fertility-restorer (R line). Fertile lines (B lines) are also required to maintain A line seed for breeding programs. We used a range of hybrids and their parental lines to assess the frequency and nature of heterosis for resistance to the whitebacked planthopper (), brown planthopper () and yellow stemborer (). Heterosis is defined as trait improvement above the average of the parental lines as a result of outbreeding. Based on the results from a greenhouse study that challenged hybrids and their parental lines with each herbivore species, we found that susceptibility to planthoppers was associated with one of the eight A lines tested, but resistance was improved by crossing with a relatively resistant restorer. Higher frequencies of heterosis for susceptibility in comparisons between hybrids and their B lines suggest that susceptibility was not related to the cytoplasmic genomes of the associated sterile A lines. Furthermore, because none of the parental lines possessed currently effective resistance genes, improved resistance against planthoppers was probably due to quantitative resistance. In a related field trial, hybrids had generally higher yields than their fertile parents and often produced larger grain; however, they were often more susceptible to stemborers, leaffolders () and other caterpillars (). This was largely a consequence of hybrid heterosis for plant biomass and was strongly affected by crop duration. We make a series of recommendations to improve hybrid breeding to reduce the risks of herbivore damage.
三系杂交水稻是通过雄性不育系（A 系）水稻与恢复系（R 系）杂交产生的。保持系（B 系）也用于为育种计划保存 A 系种子。我们使用了一系列杂交种及其亲本系来评估对白背飞虱、褐飞虱和二化螟抗性杂种优势的频率和性质。杂种优势定义为由于远缘杂交导致的性状表现优于亲本系的平均值。基于温室研究的结果，在该研究中用每种害虫对杂交种及其亲本系进行挑战，我们发现对飞虱的易感性与所测试的八个 A 系之一有关，但通过与相对抗性的恢复系杂交，抗性得到了提高。在杂交种与其 B 系的比较中，对易感性杂种优势的频率更高，这表明易感性与相关不育 A 系的细胞质基因组无关。此外，由于亲本系均不具有当前有效的抗性基因，对飞虱抗性的提高可能归因于数量抗性。在相关的田间试验中，杂交种的产量通常高于其可育亲本，并且通常产生更大的谷粒；然而，它们往往对螟虫、卷叶螟和其他毛虫更敏感。这在很大程度上是杂交种在植物生物量方面杂种优势的结果，并且受作物生育期的强烈影响。我们提出了一系列建议以改进杂交育种，降低害虫危害的风险。
