Comparative Study of Early Growth Stages of 25 Guar (Cyamopsis tetragonoloba L.) Genotypes Under Elevated Salinity.

Thar region in Pakistan has an extremely arid climate and consequently agriculture in the region is plagued with freshwater scarcity and elevated salinity. Long-term viability of agriculture in this region depends on availability of appropriate crops/cultivars that can withstand the higher salinity. Guar is considered as a viable fodder crop in the salt affected regions. This study evaluated early stage (initial 45 days) vegetative growth of 25 guar/cluster bean genotypes that were irrigated with saline (3.0, 6.0 and 9.0 dS m^-1) and harvested rainwater (control). Shoot and root length, fresh and dry weights, and accumulation of monovalent cations in the leaves were determined to evaluate plant responses after 15, 30 and 45 days of sowing. Results indicated significant reductions in shoot length, root and shoot weights and higher Na⁺ concentrations with increasing salinity. Only root length did not decrease significantly with increasing salinity. These results were used to categorize 25 guar genotypes as salt tolerant and sensitive cultivars. Our study results indicate a great potential for select cultivars of guar as a viable fodder crop in the salt affected regions of the world. The variability in growth performance of genotypes at different level of salinity warrant further examination of these results under field conditions.