英和和英

名詞

topcross (複数形 topcrosses)

1. A hybrid produced by crossing a superior or purebred male with an inferior female.
   • 1958, Dissertation Abstracts - Volume 18, page 1918:

     In 1950 and 1951 records were available on 461 purebred and topcross litters at birth and weaning, on 1051 purebred and topcross pigs in the feedlot, and on 959 carcasses from purebred and topcross pigs.

   • 1997, Maize research in 1995-96, →ISBN, page 53:

     In collaboration with the Stress Breeding Unit we evaluated a total of 787 topcrosses of various backgrounds under high and low nitrogen conditions, normal irrigation, and intermediate and severe drought stress.

   • 2009, Jeff L. Bennetzen, ‎Sarah C. Hake, Handbook of Maize: Genetics and Genomics, →ISBN, page 147:

     Early generation testing occurs around the S2 generation, which involves forming topcross hybrids between the S2 lines and an inbred line from each of the main heterotic patterns.