Desarrollo de cinco razas de amaranto (Amaranthus spp.) en Chalco, Estado de México

Abstract

FIVE RACES OF EDIBLE GRAIN AMARANTHS (AMARANTHUS HYPOCHONDRIACUS L. AZTECA, MERCADO, NEPAL AND MIXTECO AND AMARANTHUS CRUENTUS L. MEXICANO) WERE CULTIVATED FOR 149 DAYS UNDER UNIFORM CONDITIONS IN CHALCO, VALLEY OF MEXICO. PLANT HEIGHT, LEAF AREA, BIOMASS, BIOMASS ALLOCATION, GROWTH RATE WERE MEASURED PERIODICALLY. MERCADO, NEPAL AND MEXICANO REACHED THEIR MAXIMUM HEIGHT MORE RAPIDLY THAN AZTECA AND MIXTECO. THE TOTAL LEAF AREA OF THE FIVE RACES WAS SIGNIFICANTLY DIFFERENT AMONG THEM WITH MIXTECO PRODUCING THE GRATEST (1.249 M2) MIXTECO ALLOCATED (25%) OF THE STANDING BIOMASS TO REPRODUCTIVE PARTS 149 DAYS AFTER GERMINATION WHILE TYHE OTHERS ALLOCATED 50%. THE RELATIVE GROWTH RATE (RGR) WAS COMPARABLE FOR ALL RACES WITH A GENERAL DECLINE OVER TIME. THE LEAF AREA QUOTIENTS (LAR) FOR ALL FIVE RACES WERE AT THEIR MAXIMUM AT THE BEGINNING OF THE CULTIVATION AND DECLINED TO ZERO AT THE AND EXCEPT MIXTECO. THE NET ASSIMILATION RATE (ULR) WAS SIMILAR FOR AZTECA, MIXTECO AND MEXICANO ALTHOUGH THE MAXIMUM RATE FOR EACH WAS ACHIEVED AT DIFFERENT TIMES DURING THE CULTIVATION PERIOD. ON THE OTHER HAND, MERCADO AND NEPAL ATTAINED THEIR MAXIMUM NET ASSIMILATION RATES AT THE END OF THE EXPERIMENT. THE PATTERN OF AERLY BIOMASS ALLOCATION FOR REPRODUCTIVE PARTS COINCIDES WITH THAT OF PLANTS SELECTED FOR GRAIN PRODUCTION RATHER THAN FOR EDIBLE LEAVES. OF FIVE RACES, MIXTECO DID NOT COMPLETE ITS LIFE CYCLE DUE TO THE SHORTER GROWING PERIOD THAN THAT IN ITS AREA OF ORIGIN. ALSO, ITS GROWTH BEHAVIOR WITH LATER BIOMASS ALLOCATION TO REPRODUCTION MAY REFLECT CONTEMPORARY SELECTION PRESSURE FOR MULTIPLE USE INCLUDING BOTH GRAIN AND VEGETABLE.