Ligeyo Dickson O, Saina Edward, Awalla Bornface J, Sneller Clay, Chivasa Walter, Musundire Lennin, Makumbi Dan, Mulanya Mable, Milic Dragan, Mutiga Samuel, Lagat Abraham, Das Biswanath, Prasanna Boddupali M
Department of Food Crops and Research Institute, Kenya Agricultural and Livestock Research Organization, Kitale, Kenya.
Department of Horticulture and Crop Science, The Ohio State University, Wooster, OH, United States.
Front Plant Sci. 2024 Jul 1;15:1416538. doi: 10.3389/fpls.2024.1416538. eCollection 2024.
Optimization of a breeding program requires assessing and quantifying empirical genetic trends made through past efforts relative to the current breeding strategies, germplasm, technologies, and policy. To establish the genetic trends in the Kenyan Highland Maize Breeding Program (KHMP), a two-decade (1999-2020) historical dataset from the Preliminary Variety Trials (PVT) and Advanced Variety Trials (AVT) was analyzed. A mixed model analysis was used to compute the genetic gains for traits based on the best linear unbiased estimates in the PVT and AVT evaluation stages. A positive significant genetic gain estimate for grain yield of 88 kg ha year (1.94% year) and 26 kg ha year (0.42% year) was recorded for PVT and AVT, respectively. Root lodging, an important agronomic trait in the Kenya highlands, had a desired genetic gain of -2.65% year for AVT. Results showed improvement in resistance to Turcicum Leaf Blight (TLB) with -1.19% and -0.27% year for the PVT and AVT, respectively. Similarly, a significant genetic trend of -0.81% was noted for resistance to Gray Leaf Spot (GLS) in AVT. These findings highlight the good progress made by KHMP in developing adapted maize hybrids for Kenya's highland agroecology. Nevertheless, the study identified significant opportunities for the KHMP to make even greater genetic gains for key traits with introgression of favorable alleles for various traits, implementing a continuous improvement plan including marker-assisted forward breeding, sparse testing, and genomic selection, and doubled haploid technology for line development.
优化育种计划需要评估和量化相对于当前育种策略、种质、技术和政策而言，过去努力所取得的经验性遗传趋势。为了确定肯尼亚高地玉米育种计划（KHMP）中的遗传趋势，分析了来自初步品种试验（PVT）和高级品种试验（AVT）的长达二十年（1999 - 2020年）的历史数据集。采用混合模型分析，根据PVT和AVT评估阶段的最佳线性无偏估计值，计算各性状的遗传增益。PVT和AVT的籽粒产量遗传增益估计值分别为每年88 kg/ha（每年1.94%）和每年l26 kg/ha（每年0.42%），均呈显著正向。根倒伏是肯尼亚高地一项重要的农艺性状，AVT的理想遗传增益为每年-2.65%。结果表明，对大斑病（TLB）的抗性有所提高，PVT和AVT分别为每年-1.19%和-0.27%。同样，AVT中对灰斑病（GLS）的抗性也呈现出显著的-0.81%的遗传趋势。这些发现凸显了KHMP在为肯尼亚高地农业生态系统培育适应性玉米杂交种方面取得的良好进展。然而，该研究也发现，KHMP仍有重大机遇，可通过导入各种性状的有利等位基因、实施包括标记辅助向前育种、稀疏测试和基因组选择在内的持续改良计划，以及利用双单倍体技术进行品系培育，在关键性状上实现更大的遗传增益。
