Deterioração controlada de sementes de tres hibridos interespecificos de capim elefante x milheto / Controlled deterioration of seeds of three interespecific hybrids of elephant grass x pearl millet

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The interespecific hybrid Pennisetum purpureum (elephant grass) x P. glaucum (pearl millet) has been developed aiming to get the rusticity and high forage production of elephant grass and the high production of pure seeds of pearl millet. However, it revealed low phenotypic uniformity (around 50.0%) as well as low pure seed production (5 -10.0%). A recurrent selection scheme has been applied, resulting in two populations (Cutting- and Grazing-types), showing high phenotypic uniformity (around 80.0%) and a good pure seed production (around 30.0%). In order to allow the using and the establishment of those hybrid seeds, it has been necessary to analyze their performances in relation to storage conditions and controlled deterioration. Five moisture content levels and three storage temperature (40, 50 and 65°C) have been used for each hybrid. Seed sub samples for each moisture content and storage temperature combination were sealed in laminated aluminum foiled packets and stored at those temperatures until complete survival curves have been obtained. Accelerated aging test revealed vigour differences among storage periods for each hybrid as well as at 72-hour period among the hybrids. The recurrent selection has not changed seed storability of the hybrids however altered their seed sizes. The recurrent selection increased seed initial quality (Ki) and seed size for Grazing-type population (lower and high-tillered plants); however inverse results were observed at Cutting-type population (higher and low-tillered plants). Viability equation constants estimated for hybrids Cutting-type, Paraíso and Grazing-type were: e = 8,417; 7,735; 8,285; Cw = 5,037; 4,658; 4,522; Ch = 0,02309; 0,01969; 0,03655;Cq = 0,000436; 0,000403; 0,000300, respectively. It has been feasible estimating the viability equation for the hybrids, through the constants Ke = 8,033; Cw = 4,662; Ch = 0,02544; = 0,000386

ASSUNTO(S)

seleção de plantas - melhoramento genetico deterioração controlled deterioration sementes - viabilidade viability interespecific hybrids pennisetum purpureum xp. glaucum recurrent selection

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