Boron stress influences economic yield and quality in crop species

Boron plays an important role in improving the economic yield and quality of the produce. Studies conducted in refined sand at graded B levels (ranging from acute deficiency to excess) reveal that both deficiency and excess of B affect the seed quality of groundnut (Arachis hypogea L.) Var T3, sesame (Sesamum indicum L.) cv. T4, sunflower (Helianthus annuus L.) cv. NSFH-592, pigeonpea (Cajanus cajan L.) cv. UPAS, soybean (Glycine max. L.) cv. JS 80–21, blackgram (Vigna mungo L.) cv. T-9, and quality of fruit in tomato (Solanum lycoparsicum L.) var. DL-3, tubers in potato (Solanum tuberosum L.) cv. TPS and carrot root (Daccus carota L.) cv.EN. At 0.3 M B visible foliar symptoms of boron deficiency initiated in young leaves as interveinal chlorosis with marked reduction in growth. The affected leaves became thick, brittle and deshaped later turning to necrotic in prolonged deficiency. Boron toxicity symptoms initiated at > 30 M B in old leaves as chlorotic spots along with the margins. These spots enlarged, coalesced and turned necrotic. Biomass, weight of pods and seeds were maximum at 30 μM B. Low (<30 M B) as well as high (> 30 M B) B reduced the economic yield and deteriorated the quality of the produce by lowering the concentration of starch, protein in seeds and storage organs, lycopene and ascorbic acid in tomato fruits and oil in oil seeds. The concentration of sugars and phenols was enhanced in B deficiency in all crops except in sunflower, potato and carrot where the of sugar content decreased in B stress (deficiency as well as excess B) condition whereas excess B reduced the sugar concentration in sesame and pigeonpea seeds. The concentration of boron in different parts paralleled with the increase in boron supply. Critical B concentration has been worked out in the edible and economically important plant part for each species.