Differences in growth and productivity between genotypes of common bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata L.) in the Sadovo region of Bulgaria

The study examined the differences between 10 accessions of common bean and cowpea during the vegetation period. Different stages of development and elements of yield were analysed in the climatic conditions of Sadovo (Bulgaria), which is characterised by hot summers and insufficient rainfalls. All genotypes were planted in the second 10 days of April. They emerged 10-15 days after sowing. The flowering stage occurred after 28-34 days in common bean and 45-60 days in cowpea. The vegetation period duration was much longer in cowpea (over 98 days) than in the common bean (less then 80 days). The reproductive organs (number of pods and seeds per plant, size of pods and seeds, weight of pods and seeds per plant) were quite different for the two crops. The mean number of pods per plant was 8.84 in common beans and 13.22 for cowpea; the number of seeds per pod was 4.05 for beans 10.56 for cowpea; the number of seeds per plant was 25.65 for beans and 93.47 for cowpea. The bean seeds were larger than the cowpea seeds, with 100-seed weights of 41.86 g and 15.73 g, respectively. Under the climatic conditions of Sadovo, the cowpea accessions showed a more stable yield, resulting in more pods and seeds per plant and weight of seeds per plant, when compared with common bean accessions.