Ambrósio Moisés, Daher Rogério Figueiredo, Silva Santana Josefa Grasiela, Leite Cleudiane Lopes, Duarte Joao Victor Bousquet, Vidal Ana Kesia Faria, Nascimento Maxwel Rodrigues, de Souza Alexandre Gomes, Freitas Rafael Souza, Stida Wanessa Francesconi, Farias João Esdras Calaça, Santos Raiane Mariani
Center for Agricultural Sciences and Technologies, State University of North Fluminense Darcy Ribeiro, Avenida Alberto Lamego, 2000, Parque Califórnia, Campos dos Goytacazes, RJ, 28013-602, Brazil.
Sci Rep. 2024 Aug 1;14(1):17850. doi: 10.1038/s41598-024-68466-9.
The State University of North Fluminense Darcy Ribeiro (UENF) has been developing for fifteen years a breeding program that aims at the development of new cultivars of elephant grass due to its high potential and the low availability of cultivars developed by genetic breeding programs that meet the needs of producers in the State of Rio de Janeiro. In this sense, inbred families were also obtained as a way of fixing potential alleles for traits related to production, as the inbreeding process apparently does not strongly affect elephant grass in aspects related to inbreeding depression. This study aimed to estimate genetic diversity, variance components and prediction of genotypic values in 11 (S) elephant grass families, and perform the truncation and simultaneous selection of traits using the selection index, by mixed models. The experimental design consisted of randomized blocks with 11 (S) families, three replications, and six plants per plot. For variables dry matter production, percentage of dry matter, plant height, stem diameter, number of tillers and leaf blade width, was performed the estimation of genetic parameters and selection of the best genotypes based selection index using mixed model. The descriptors were subjected to correlation analysis, distance matrices were generated by the Mahalanobis method, and individuals were grouped by the UPGMA method. In the selection via mixed models (REML/BLUP), families 6, 11, 8, 1, 3, 7, and 9 contributed most of the genotypes selected for the evaluated traits, indicating their high potential to generate superior genotype. The selection indices via mixed models indicated that the multiplicative index presented a greater selection gain.The phenotypic correlations showed the possibility of performing an indirect selection from six evaluated traits.The genotypes were separated into 18 groups by the Mahalanobis distance, allowing the observation of a wide genetic diversity. The most divergent and productive genotypes were self-fertilized to obtain the second generation (S), continuing the development program.
北弗卢米嫩塞州立大学达西·里贝罗分校（UENF）十五年来一直在开展一项育种计划，旨在培育象草新品种。这是因为象草潜力巨大，而能满足里约热内卢州生产者需求的通过遗传育种计划培育出的品种却很少。从这个意义上说，还获得了近交系家族，以此来固定与生产相关性状的潜在等位基因，因为近交过程在与近交衰退相关的方面显然对象草影响不大。本研究旨在估计11个（S）象草家族的遗传多样性、方差成分和基因型值预测，并通过混合模型使用选择指数进行性状的截断选择和同时选择。实验设计为随机区组，有11个（S）家族，三次重复，每小区六株。对于干物质产量、干物质百分比、株高、茎直径、分蘖数和叶片宽度等变量，使用混合模型进行了遗传参数估计和基于选择指数的最佳基因型选择。对描述符进行了相关性分析，通过马氏距离法生成距离矩阵，并通过UPGMA法对个体进行分组。在通过混合模型（REML/BLUP）进行的选择中，6、11、8、1、3、7和9号家族贡献了大部分为评估性状所选的基因型，表明它们具有产生优良基因型的巨大潜力。通过混合模型的选择指数表明，乘法指数具有更大的选择增益。表型相关性表明从六个评估性状进行间接选择的可能性。通过马氏距离将基因型分为18组，从而可以观察到广泛的遗传多样性。将最具差异和生产力的基因型进行自交以获得第二代（S），继续开展育种计划。
