Root attributes and seedling biomass of old and modern soybean cultivars under water deficit
The water deficit in the initial soybean root growth may impair the crop establishment and force the grower to perform a re-seeding. This problem has occurred in some producing regions of Brazil and according to the predictions of climate change may become an increasingly frequent condition. Characterizing and identifying cultivars with characteristics of water deficit resilience are important for the development of improved cultivars in the future. Seedlings of four soybean cultivars were evaluated, being two old and two modern, with and without water deficit. The method used in this work evidenced that there is interaction between cultivar and water deficit in the growth of soybean seedlings. This method can be replicated for a mass prospection of cultivars in search of resilience to the water deficit, since it can be evaluated in a short time span. Soybean seedlings evaluated under water deficit condition increased the biomass root partition with different changes in root attributes. The modern cultivars increased the root length in water deficit, evidencing that this characteristic was selected by breeding, even if indirectly. The cultivars used in this study can be classified in relation to the water deficit as follows: sensitive - Santa Rosa; intermediary - Embrapa 48 and BRS 284; and less sensitive TMG 7262.