Differences in drought tolerance between cultivars of field bean and field pea. Morphological characteristics, germination and seedling growth

Different responses among legume species were observed, but the morphological and physiological differences that confer drought resistance or susceptibility are not well explained. The objective of this study was the determination of variation of morphological characteristics within 7 field bean and 4 field pea cultivars as related to drought tolerance. Also differences in the effect of drought on seed germination and seedling growth in 2 field bean and 2 field pea cultivars of different drought tolerances were investigated. The examined cultivars were characterized by variation of certain morphological characteristics regarded as xeromorphic features associated with the ability of plant to survive under drought. The drought resistant cultivars (field bean Gobo and field pea Solara) in comparison with the sensitive ones (field bean Victor and field pea Bareness) were characterized by more favourable relations between the size of the above—ground parts and the size of root, as well as the frequency and size of stomata. Moreover, in the resistant cultivars there was observed, a smaller influence of simulated drought (ψ=−0.6 MPa) on the increase of dry matter of the above-ground parts and of the roots. Also there was smaller influence on the height of seedlings and on the length of lateral roots. The correlation coefficients between the measured characteristics and the values of the drought susceptibility index (DSI) were in most cases statistically not significant, although, on the whole, they were very high. This may be an indication of a relatively high participation of the measured characteristics in the total variation of the drought tolerance in the cultivars. In cultivars regarded as belonging to the group of sensitive ones, a more disadvantageous effect of simulated drought (ψ=−0.6 MPa) on seed germination was observed, especially in the determination of the promptness index (PI).