Callogenesis optimization of guar (Cyamopsis tetragonoloba L.) by altering hormonal compositions and explant types

Abstract

Callus production and regeneration can greatly help in improving the progress of genetic modification and help in gene transfer. Accordingly, this study investigated the optimal medium for callus formation based on varying levels of growth regulators. The experiment was performed in a factorial experiment based on a completely randomized design in 5 replications with hormonal composition (13 levels) and explant types (3 levels) as factors. The levels of hormonal composition were containing NAA, BAP, 2, 4-D and Thidiazuron (TDZ) applied to the MS media. Explant types, including leaf, stem, and rootlet, were disparted from the produced explants. After 80 days, the explants were measured for various traits, including days to callus formation, callus formation percentage, fresh and dry weight, mass moisture percentage. According to analysis of variance, hormonal composition, the type of explant, and their interaction had significant effects on fresh and dry weight and callus formation. 2, 4-D (2 mg/l) + TDZ (2 mg/l) and NAA (2 mg/l) + BAP (1 mg/l) treatments had the highest and lowest percentage of callus formation, respectively. The correlation test revealed a significant relationship between callus formation and both fresh weight and mass moisture percentage. However, this trait did not show a significant correlation with dry weight. In general, treating leaf explant with the TDZ hormone resulted in the highest dry and fresh weights compared to treating root explant with the BAP hormone. To enhance callus production and achieve better weight in this plant, it is recommended to use leaf explants combined with TDZ(2mg/l) and 2,4-D(2mg/l) hormone treatment.