The Effect of Foliar Application of K2SO4 or KH2PO4 on Skin Color of the ‘Kyoho’ Grape

Abstract

Anthocyanins in red grape skin have a positive effect on fruit color and human health. The effect of foliar potassium application on anthocyanin accumulation in grape skin is not well understood. The study aimed to better understand the mechanism of anthocyanin accumulation in grape skin in response to foliar sprays of K2SO4 and KH2PO4. In this study, we investigated the effects of foliar application of KH2PO4 (T2), K2SO4 (T1) and distilled water (CK) on the skin color of ‘Kyoho’ grapes at mid-ripe and mature stages. At 90 and 110 days after full bloom (DAFB), T2 had the greatest total soluble solids (TSS), flavonoid and total anthocyanin contents, followed by T1 and CK. At two stages, the titratable acid content decreased and the juice pH increased under T2 treatment relative to CK. T1 and T2 had lower lightness (L*) than CK, and the color index of red grapes (CIRG) under T1 and T2 increased at two stages compared to CK. KEGG metabolic pathway analysis revealed that flavonoid biosynthesis was the most significantly enriched pathway in CK vs. T2 at 90 and 110 DAFB. At 90 DAFB, T2 had higher expressions of phenylalanine ammonia-lyas (PAL), cytochrome P450 CYP73A100 (CYP73A), 4-coumarate: CoA ligase (4CL), chalcone synthase (CHS), flavanone 3-dioxygenase-like (F3H) and UDP glucose: flavonoid 3-o-glucosyl transferase (UFGT) than CK and T1. Foliar application of potassium fertilizer may accelerate anthocyanin accumulation by altering the transcript levels of PAL, CYP73A, 4CL, CHS, F3H, and UFGT of the flavonoid biosynthesis.

Effect of some Safe Alternatives on Yield, Fruit Quality and Gray Mold Disease Control of King Ruby Grape

“…Generally, all harvest day results reveal that K-salts applied in this study have various positive effects on grape definitely enhanced cluster weight, berry volume, due to expansion depending on osmotic regulation, sugar accumulation and cellular growth and free tartaric acid decrease, a main organic acid in grape, sub sequentially decreasing juice pH that alters red color quality (Obenland et al, 2015 andWu et al, 2021). Moreover, berries firmness and adherence readings are in harmony with Khalifa and Thabet (2014) and Riya, Johnson et al (2022) findings.…”

Effects of foliar‐sprayed potassium dihydrogen phosphate on accumulation of flavonoids in Cabernet Sauvignon (Vitis vinifera L.)

“…and Mpelasoka et al 19 . P and K participate in the transport of sugar and acid, the response of hormones, and the synthesis of polyphenols related to color and aroma 23,24 . Moreover, exogenous P and K fertilizers can promote the accumulation of soluble solids and anthocyanin in grapes 24,25 …”

“…16,21,22 The role of P and K nutrition on yields and fruit quality in grapevines has been reviewed by Brunetto et al 11 and Mpelasoka et al 19 P and K participate in the transport of sugar and acid, the response of hormones, and the synthesis of polyphenols related to color and aroma. 23,24 Moreover, exogenous P and K fertilizers can promote the accumulation of soluble solids and anthocyanin in grapes. 24,25 Traditionally, most plants mainly take up P and K applied to the soil through the roots.…”

“…23,24 Moreover, exogenous P and K fertilizers can promote the accumulation of soluble solids and anthocyanin in grapes. 24,25 Traditionally, most plants mainly take up P and K applied to the soil through the roots. However, excessive soil fertilization has caused some serious problemsfor example, pollution of the environment and a change in soil propertiesbecause most of the applied fertilizers are not absorbed by plants.…”

Influence of mineral fertilizers on the growth, development and productivity indicators of large clustered grapes

“…Providing the population of Uzbekistan with high-quality industrial grapes and processed wine products is one of the urgent tasks facing entrepreneurs [1]. The soil and climatic conditions of Uzbekistan make it possible to provide our people with inexpensive, vitaminrich, tasty grape products and wines throughout the year [2,3].…”