Grain yield of NS maize hybrids representing different eras of breeding

Abstract

During the past decade, the current commercial maize hybrids had been rapidly substituted by new selected cultivars (in regards to the previous 30 years) so that estimated "hybrid-commercial life" (cycle) appears to be reduced from the 10 years to the 5 years period. Our objective for this study was to test grain yield differences among NS maize hybrids representing different eras of breeding (realized from the 1989 to the 2004) We used the results from the post-official trials evaluated at seven locations in 2005. The hybrids grain yield increased at a rate (measured by regression coefficient) of 0.28t/ha per cycle, or about 56kg/ha per year. The results of polynomial ANOV-a regression model showed significant (P lt 0.05) value for the linear effect only. On the same time, the relative contribution of the quadratic and cubic sum of squares to the hybrids (cycles) sum of square were negligible (F lt 1).

Brža zamena postojećih hibrida novim selekcijama, karakteriše naše tržište hibridnog kukuruza u protekloj deceniji, sa tendencijom da se prosečan "komercijalni vek" jednog hibrida skrati sa deset na oko pet godina. Cilj ovoga rada je bio da testira razlike u prinosu zrna četiri NS hibrida kukuruza, predstavnika različitih perioda (ciklusa) selekcije (priznatih od 1989-2004. godine). Korišćeni su rezultati postkomisijskih ogleda sa sedam lokaliteta u 2005. godini. Povećanje prinosa zrna (izraženo koeficijentom linearne regresije) iznosio je 0.28 t/ha/ciklusu, ili približno 56 kg/ha/godini. Rezultati ANOV-a polinomne regresije pokazuju signifikantnu vrednost (P lt 0.05) samo za linearni efekat, dok su proporcije sume kvadrata kvadratnog i kubnog efekta, u sumi kvadrata hibrida bile zanemarljive (F lt 1).