RELATIONSHIPS BETWEEN BIOMASS YIELD, GRAIN PRODUCTION, LODGING SUSCEPTIBILITY AND FEEDING VALUE IN SILAGE MAIZE

The general combining ability of eleven maize lines, crossed with four tester lines, experimented in a multilocal network, were studied in o rder to investigate the relationships between biomass yield, grain pro duction, root and stalk lodging, and feeding value characteristics. A high biomass yield was not associated with a low stover feeding value, because a greater development of the plant is probably linked to an i ncrease in the amount of both sclerified and parenchymatous tissue. A great genetic variability for the grain filling process was pointed ou t; that could be seen as both the occurence of different sources of as similates, and a variation in the grain/stover ratio. Furthermore, it appeared that: root and stalk lodging resistance was not achieved at t he expense of the stover quality one possible reason could be that the distribution of the cell-wall constituents in the stalk is as importa nt for stem stiffness as their content. Finally, considering lines of comparable earliness to get rid of the effect of maturity, it was conc luded that, neither biomass or grain dry matter yield nor root and sta lk lodging are inter-related or related to feeding value characteristi cs (e.g. whole-plant composition, stover composition and digestibility traits). It was particularly noticed that some lines displayed all th e favourable characters. These results therefore make one think that b reeders could simultaneously improve productivity, lodging resistance and feeding value of silage maize.