Exploring the relationship between leaf color, canopy architecture,photosynthesis and pigment composition in guava mapping population

Leaf color is a crucial parameter in determining the photosynthetic productivity of a plant. We examined 150 intervarietal guava hybrids from the cross Arka Poorna x Purple Local, that were segregating for leaf color (green and greyed purple). Variations in tree morphology, gas exchange parameters and pigment contents were investigated to understand the impact of leaf color on plant growth and physiology. Significant differences were observed in tree morphology between green and purple leaves, with green leaf plants showing better growth and vigor than purple leaf individuals. Photosynthetic rate, stomatal conductance, and transpiration rates were significantly higher in green plants than in purple leaf plants. In contrast, chlorophyll b, total chlorophyll, carotenoids, and anthocyanins were significantly higher in the purple plants. These results suggest that the presence of high anthocyanin and carotenoid pigments in purple plants have a masking effect that resulted in high chlorophyll production and low photosynthetic rates due to reduced incident light. The segregating population is an important repository for mapping QTLs associated to photosynthetic attributes.