Schuster Andreia, Santana Alice Silva, Uberti Alison, Dias Fabíola Dos Santos, Dos Reis Helber Moreira, Destro Vidomar, DeLima Rodrigo Oliveira
Department of Agronomy, Universidade Federal de Viçosa, Viçosa, Brazil.
Corn Breeding Department, Tropical Melhoramento e Genética, Sorriso, Brazil.
Front Plant Sci. 2024 Oct 1;15:1429901. doi: 10.3389/fpls.2024.1429901. eCollection 2024.
The tropical maize breeding for low-P tolerance and good performance under low-P stress environments can be achieved through selection based on root morphology traits at seedling stage. Here, we assessed the genotypic variation and genetic diversity of a panel of 151 tropical maize inbred lines for root and shoot seedling traits, investigated the relationship among traits and selected a set of promising inbred lines for low-P tolerance and performance. We evaluated the inbred lines at seedling stage in a greenhouse experiment under two conditions: applied P (AP) and non-applied P (NAP). A mixed model approach was used to estimate variance components and predict the genotypic values of each inbred line. The genetic diversity among inbred lines based on root and shoot traits was assessed, and correlations were estimated between tested traits under AP and NAP. Our panel of inbred lines showed huge genetic variability for all traits and presented large genetic diversity under both P conditions. Variance components due to the inbred line × P condition interaction were also highly significant ( < 0.01) for all traits. Root dry weight (RDW) was positively associated with stalk dimeter (SD), shoot dry weight (SDW) and root length, volume, and area under both P conditions. Also, the SD and SDW were associated with most root traits under AP. Based on low-P tolerance and performance indices, we selected a set of top 20 inbred lines to be used in our maize breeding program. We therefore concluded that there is a significant genetic diversity in the tropical maize inbred lines which have the genetic potential to be use in association mapping studies and also to develop improved low-P tolerant and P-efficient hybrids and maize breeding populations for low-P stress environments.
通过在苗期基于根系形态性状进行选择，可以实现热带玉米在低磷胁迫环境下的耐低磷育种及良好表现。在此，我们评估了151份热带玉米自交系组成的群体在根系和地上部苗期性状的基因型变异和遗传多样性，研究了性状间的关系，并筛选出一组具有耐低磷能力和良好表现的有前景的自交系。我们在温室试验中于两种条件下对自交系进行了苗期评估：施磷（AP）和不施磷（NAP）。采用混合模型方法估计方差分量并预测每个自交系的基因型值。评估了基于根系和地上部性状的自交系间的遗传多样性，并估计了AP和NAP条件下各测试性状间的相关性。我们的自交系群体在所有性状上均表现出巨大的遗传变异性，且在两种磷条件下均呈现出较大的遗传多样性。所有性状的自交系×磷条件互作引起的方差分量也极显著（<0.01）。在两种磷条件下，根干重（RDW）均与茎粗（SD）、地上部干重（SDW）以及根长、根体积和根面积呈正相关。此外，在AP条件下，SD和SDW与大多数根系性状相关。基于耐低磷能力和表现指数，我们筛选出了一组排名前20的自交系用于我们的玉米育种计划。因此，我们得出结论，热带玉米自交系中存在显著的遗传多样性，这些自交系具有用于关联作图研究以及培育改良的耐低磷和磷高效杂交种及玉米育种群体以适应低磷胁迫环境的遗传潜力。
