PHOTOSYNTHESIS AND GENETIC RELATIONSHIPS IN THE GENUS VIGNA

Legumes are important plant species for human nutrition and the environment through their provision of protein in diets and nitrogen fixation. Species in the genus Vigna have great potential to fight malnutrition and hunger. Unfortunately, there are limited scientific studies reported on the genus Vigna. The main constraint on species in the genus Vigna is low yield. Photosynthesis, which is a key life process in plants, has not received in depth studies in the genus Vigna. Moreover, an understanding of genetic relationships between and within species in the genus Vigna is essential for the genetic improvement of Vigna spp. Experiments were carried out in a plant growth chamber to evaluate photosynthetic rate under different light intensities and CO₂ concentrations. Results showed variations between and within cultivated and wild species in parameters such as light saturated maximum photosynthesis (A_max), light compensation point (LCP), and light saturation point (LSP) and maximum rate of carboxylation by Rubisco (V_cmax). In the present study, the results showed that there is significant effect of plant genotype on LCP (F_{(4, 5)}=16.55, P<0.01, r²=0.63), A_max (F_{(4, 5)}=5.60, P<0.05, r²=0.67), and LSP (F_{(4, 5)} =7.73, P<0.05, r²=0.49). The results also showed that there is significant effect of plant genotype on J_max (F_{(4, 5)}=20.95, P<0.01, r²=0.67) and V_cmax (F_{(4, 5)}=11.28, P<0.05, r²=0.38). Genetic studies focused on the study of genetic diversity and the transferability of markers across Vigna spp. We present results of potential COS and SSR primers that showed amplification products and transferability across 38 species in the genus Vigna.