Genetic control of adaptive root characteristics in white clover

• Published in: Plant and Soil Vol. 200; no. 1; pp. 63 - 69
• Main Authors: Caradus, J.R. (AgResearch Grasslands, Palmerston North (New Zealand).), Woodfield, D.R
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01.03.1998; Springer; Springer Nature B.V
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Biological and medical sciences; Clover; Cultivars; Drought; DROUGHT STRESS; ESTRES DE SEQUIA; Fibrous roots; Fundamental and applied biological sciences. Psychology; Genetic variation; Genetics and breeding of economic plants; GENOTIPOS; GENOTYPE; GENOTYPES; Grasslands; Leaves; Plant growth; Plant roots; Plants; RACINE; RAICES; Ratios; Root growth; ROOT SYSTEMS; ROOTS; SELECCION; SELECTION; SISTEMA RADICULAR; Stolons; STRESS DU A LA SECHERESSE; SYSTEME RACINAIRE; TRIFOLIUM REPENS; Varietal selection. Specialized plant breeding, plant breeding aims; Genetic variability; Nutrition; Root; Characteristic; Genetic determinism; Stress; Leguminosae; Drought resistance; Dicotyledones; Morphology; Angiospermae; Humidity; Spermatophyta; Fodder crop; Intraspecific comparison; Trifolium repens; Adaptation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1023/A:1004296707631

Comparison of 11 white clover genotypes revealed a 3-fold variation in taproot diameter and proportion of fibrous roots to total root dry weight varied from 0.45 to 1.00. Shoot type, determined by leaf size, was positively correlated with taproot diameter and number of vertically penetrating roots (r = 0.86 and 0.95, respectively, P < 0.001, df = 9), but negatively correlated with proportion of fibrous to total root dry weight (r = -0.87, P < 0.001, df = 9). Three cycles of selection for taproot diameter were carried out in one population, with a response to selection of 2.4% per cycle. Divergent selection for taproot diameter and for root weight ratio (proportion root weight to total plant weight) was done in two different populations. The impact of the divergent taproot and root weight ratio selections on performance was assessed under grazing in a drought-prone environment and in a controlled-environment study, respectively. Selection for medium leaf size and large taproot diameter gave yields 70% better in moist conditions and 35% better under dry conditions than that of the standard cultivar, Grasslands Huia. Selection for increased root weight ratio was also effective in improving growth and survival in drought prone environments. Selection for specific root characteristics has improved yield and persistence in drought prone environments.