‘Tepehuán-RS’ a new drought tolerant, high grain yield in low plant densities and slow darkening pinto bean cultivar

‘Tepehuán-RS’ (Reg. no. CV-365, PI 706601), tested as line P-SALTILLO×TA-245-1-2-4, is a new drought-tolerant and slow darkening pinto bean cultivar (Phaseolus vulgaris L.). Tepehuán-RS showed high grain yield in low plant densities. It was jointly developed by INIFAP, Postgraduate College and Autonomous University of Chihuahua, released by INIFAP-Sierra of Chihuahua Experimental Station. Bean is one of the most important crops in Mexico by sown area, with 1.4 million ha. The mean bean yield in Mexico is 520 kg·ha⁻¹ in rainfed conditions. Production is considerably affected by two main problems, drought and low densities of sown and harvested plants. This sparse plant cover exposes the soil for a longer period, leading to increased water loss through evaporation and exacerbating drought stress. Tepehuán-RS emerges as the superior variety in all environments studied during 2022 and 2023 with a mean yield of 2125.9 kg·ha⁻¹. While the control Pinto Saltillo showed a yield of 1818.4 kg·ha⁻¹, Tepehuán-RS produced 12.9% more than Pinto Saltillo. When analyzing all environments with drought, in 2022 and 2023, Tepehuán-RS was the best with a yield of 1645.7 kg·ha⁻¹. Under these conditions, Pinto Saltillo presented a yield of 1168.4 kg·ha⁻¹. Interestingly, Tepehuán-RS surpassed the control by a remarkable 41.8%. This variety presents the best grain yield even at low plant densities and field irrigation-drought experiments. Genetic markers and pathogen testing indicate Tepehuán-RS has the I gene for resistance to Bean common mosaic virus, the Co-4² gene for anthracnose resistance, and molecular marker Pvsd-1157 linked to slow darkening gene sd sd of the seed coat.