Diversidade de populações segregantes de soja para o oeste do estado do Paraná

Abstract

The diversity of segregating soybean populations is fundamental for the selection oflines that are increasingly adapted and stable to the region and that take advantage of the cultivar x environment interaction. The new soybean populations obtained from cultivars adapted to the regional photoperiod with degrees of relative maturity appropriate to the region are fundamental for farmers' acceptance of the new cultivars. Thus, the objective of this work was to evaluate the genetic diversity and adaptability of segregating soybean populations and select plants with agronomic value for the Western Paraná region at low altitudes and high temperatures. Nine soybean populations were obtained from the crossing of cultivars with relative maturity levels between 5.0 and 6.5. F2 generation plants were evaluated in the field with late sowing to evaluate sensitivity to photoperiod. Five hundred plants were evaluated for the productivity components days until the beginning of flowering, cycle until physiological maturity, first pod and harvest heights, number of stems and number of pod/plant in addition to descriptors such as pubescence color, pod, grain and hilo, among others. In all populations, lines with greater productive potential than the control were obtained with a GMR of 5.8 to 6.2. The genetic variability of the populations was wide for characteristics related to production components. Genetic diversity indicated the qualitative and cycle length variables as the most important for differentiating populations. Thus, it is concluded that: the segregating soybean populations present genetic variability and adequate averages for characteristics of economic importance and possible to be improved with a view to obtaining strains adapted to the region; the segregating population derived from the cross Delta 59I60 IPRO RSF x BS 2606 IPRO associates high grain productivity with lower GMR and higher plant height, being the most promising among them.