Productiveness and nodule ability of different varieties of common bean ( Phaseolus vulgaris L.) in Urals conditions

Common bean ( Phaseolus vulgaris L.) has a high nutritional value, its seeds contain a significant amount of protein and essential amino acids and vitamins. Furthermore, it can accumulate organic nitrogen in the soil due to nitrogen fixation. On the territory of the forest-steppe zone of Urals (Bashkortostan) in small plot experiments in homogeneous soil conditions during five years the elements of yield structure of four cultivars of common bean (Gornal, Ufimskaya, Zolotistaya and Elsa) were studied. In different soil and climatic conditions the distribution character (skewness) of seed production and nodule activity were compared. Сorrelations between agro-meteorological factors, nodules number and productivity were determined. In one of these experiments there were watering and using of start doses of fertilizers (PK) 45. The remaining experiments were carried out in a natural agricultural background without irrigation. The seeds yield of local cultivars (Gornal, Ufimskaya, Zolotiataya) in homogeneous soil conditions on leached chernozem (Ufa district) ranged from 18 to 22 kg/ha. High seed productivity of a new cultivar Elsa was mentioned. In the experiments without irrigation (Ufa, Iglinskiy, Chishminskiy, Bakalinskiy areas) the seed weight of different cultivars changed depending on the agro-meteorological conditions from 4 to 17 g/plant, being doubled at watering. An average rang of seed production variation for all years was 50 % for Zolotistaya cultivar, 53 % for Elsa, 57 % for Ufimskaya and 76 % for Gornal cultivars. The close relationship ( r = 0.61) between the productivity of beans and the sum of active temperatures above 15 °С was revealed. Greater flexibility to the amount of heat was shown in the locally bred varieties Zolotistaya and Ufimskaya at r = 0.46 and r = 0.59, respectively, greater dependence on abiotic factors was demonstrated by Gornal and Elsa varieties at r = 0.78 and r = 0.84, respectively. Similar relations were revealed when the analysis of correlative links was made between the duration of the period of above 15 °С temperatures and the seed productivity. Thus, correlation was detected at r = 0.42 and r = 0.20 for Zolotistaya and Ufimskaya cultivars, and at r = 0.51 and r = 0.69, for Gornal and Elsa, respectively. In different conditions there were from 5 to 29 nodules formed at a plant. The average variation of nodule activity between all cultivars during all years was 15.3 %. However, for each cultivar under different soil and climatic conditions the individual average coefficients of variation differed, being 44 % for Gornal, 59 % for Zolotistaya, 65 % for Ufimskaya and 18 % for Elza varieties. In most experiments the positive skewness prevailed in both the number of nodules and productivity. Normal distribution and the negative skewness for all cultivars were observed in the experiment with watering, and occurred more frequently in plants of Zolotistaya cultivar. Number of nodules per plant and seed production correlated ( r = 0.75-0.87) only under optimal water regime and mineral nutrition. On the gray forest soil the plants formed a symbiosis with local rhizobia, and on the chernozem soil the symbiotrophic nitrogen nutrition prevailed over mineral nitrogen one. The revealed high intravarietal variability of common bean plants and the asymmetric distribution of symbiotic activity and productivity suggest the possibility for selecting lines to improve the efficiency of symbiosis. A randomly formed supernodulating hybrid L20 of cultivar Elza was discovered to be promising for further breeding.