Caracterização fenotípica e diversidade genética em soja transgênica

Abstract

Genetic improvement associated with the progress in production technology has enabled Brazil to become the world’s largest soybean producer. The focus of improvement programs is to develop superior crops with high seeds yield productivity, resistance to pests and diseases, and tolerance to abiotic stress. Therefore, to support genitors selection, given researchs attesting to Brazil's narrow soybean genetic basis, genetic diversity studies aid in genitors selection. The goal of this paper is to characterize and assess genetic divergence in fifteen transgenic soybean crops, and indicate which are more promising. The research was performed at Fazenda Nossa Senhora da Aparecida belonging to the company Agropecuária JP LTDA, located at KM683 of the Brazilian Federal Highway No. 365, in the outskirts of the city of Monte Alegre de Minas, in the state of Minas Gerais. Fifteen transgenic soybean crops were assessed in a randomized complete block design with four replications. Manual seeding on soybean straw was performed on March 20th, 2021. Cultural traits and pest and disease control were performed as per the culture’s technical recommendations. The following features were assessed: number of days for blooming and maturity, plant’s height at blooming and maturity, number of knots in the main stem at blooming and maturity, insertion height of the first pod, number of total pods per plant, number of pods containing 1, 2, and 3 seeds, weight of 100 seeds, and seeds yield. The crops showing the highest seeds yield was FOCO IPRO - 74I77 RSF, 96R29IPRO, M6210IPRO, and NK7201IPRO, with means of 1862.46 kg ,1678.99 kg, 1623.82 kg, and 1578.70 kg, respectively. The generalized Mahalanobis distance ranged from 4.6 between the APORÉ 75HO111 IPRO and M6410iPRO crops, up to 110.70 between NS 7670 RR and 98Y30. From this genetic distance it was possible to obtain a dendrogram using the UPGMA method and Tocher clustering, enabling the crops to be separated into four groups. The crops showing the highest seeds yield were FOCO IPRO - 74I77 RSF, 96R29IPRO, M6210IPRO, and NK7201IPRO, with means of 1862.46 kg,1678.99 kg, 1623.82 kg, and 1578.70 kg, respectively. Upon analyzing the cycle, yield, number of pods, pests and diseases resistance characteristics already present in the following hybridisations are suggested: NS7670RR and 98Y30, FOCO IPRO – 74I77 RSF and 97R50IPRO, FOCO IPRO – 74I77 RSF and 98Y01IPRO, FOCO IPRO – 74I77 RSF and 98Y30, 97R50IPRO and 98Y30, 98Y01IPRO and 98Y30, FOCO IPRO – 74I77 RSF and NS7670RR, NS7670RR and 97R50IPRO, NS7670RR and 98Y01IPRO.