Using climatological, geographical, and taxonomic information to identify sources of mature-plant salt tolerance in alfalfa

• Published in: Crop science Vol. 34; no. 3
• Main Authors: Smith, S.E, Johnson, D.W, Conta, D.M, Hotchkiss, J.R
• Format: Journal Article
• Language: English
• Published: 01.05.1994
• Subjects: AGUA DE RIEGO; AGUA SALINA; ALIMENT POUR ANIMAUX; CLIMA; CLIMAT; COLECCION DE PLANTAS; COLLECTION BOTANIQUE; EAU D'IRRIGATION; EAU SALINE; GERMOPLASMA; INTRODUCCION DE PLANTAS; INTRODUCTION DE PLANTES; MATERIEL GENETIQUE; MEDICAGO SATIVA; PIENSOS; PROCEDENCIA; PROVENANCE; RENDEMENT DES CULTURES; RENDIMIENTO DE CULTIVOS; TAXONOMIA; TAXONOMIE; TOLERANCE AU SEL; TOLERANCIA A LA SAL; VARIACION GENETICA; VARIATION GENETIQUE; VARIEDADES DE ALTO RENDIMIENTO; VARIETE A HAUT RENDEMENT
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci1994.0011183X003400030017x

Performance under salinity stress has been improved in elite populations of alfalfa (Medicago sativa L. sensu lato) by mass selection. Use of unimproved germplasm may permit additional gains in salt tolerance or access to unique tolerance mechanisms. Resources would be used more efficiently if germplasm with specific traits could be identified from large collections using taxonomical, climatological, or geographical data. Our objective was to determine whether such information could be used to identify M. sativa accessions in the U.S. plant introduction (PI) collection likely to have improved response to salinity. We evaluated forage yield for three harvests in 630 PIs under saline (80 mM NaCl) and nonsaline irrigation in greenhouse trials. Passport data were used to classify climate (Trewartha's system) at the collection site. No significant differences were found in mean salt tolerance (forage yield with saline irrigation/nonsaline irrigation) among the subspecies of M. sativa sampled extensively (falcata, caerulea, varia, and sativa). Accessions considered either tolerant or with high saline yield (high forage yield with saline irrigation; highest 15.1% of accessions for these traits) were present in an subspecies. Mean salt tolerance and saline yield for accessions, and the proportion of accessions considered tolerant or with high saline yield did not differ between accessions from six basic climate groups (Tropical, Arid, Subtropical, Temperate, Boreal, Highland). An increased proportion of tolerant accessions was found from arid environments where alfalfa is usually grown without irrigation. The effects of agronomic practices seems to represent a major limitation to use of climatological data in identifying germplasm with improved performance under salinity stress