Morphological development of Alfagraze cultivar and Crioula alfalfa populations selected at the seedling stage

Abstract

The objective of this study was to compare two populations of Crioula alfalfa cultivars, selected by the length of the seedling second internode (Crioula-LI, long internode = 2.5 cm; Crioula-SI, short internode = 1.5 cm) with Alfagraze cultivar in order to verify the seedling morphology value for the selection of more prostrate plants. The plants were grown individually in pots in a semi-protected environment and harvested at 74, 104, 134, 164, 194 and 224 days. Crioula populations varied in terms of height, leaf area, root volume, dry matter yield, and the Crioula-LI population outnumbered that of Crioula-SI. For height, length of internode and primary stem, Alfagraze (45.1 cm, 2.1 cm and 16.7 cm) was similar to Crioula-SI (37.6 cm, 2.3 cm and 18.2 cm); however, the leaf area (2.028 cm²) and dry matter yield (20.3 g) did not differ from those of Crioula-LI (2.021 cm², 21 g). The Alfagraze cultivar surpassed the Crioula population in terms of procumbency, crown diameter and crown stem number. At the flowering stage, the Crioula-LI cultivar had total stem number (61/plant) higher than Alfagraze (47/plant) and Crioula-SI (41/plant) cultivars. The length of the seedling internode is a promising marker for the selection of alfalfa, being a predictive factor for plant height, stem number, root volume and leaf area, and can be useful in the alfalfa breeding.