The concept of combining (i.e., integrating) data obtained from intercrosses
of several inbred strains (i.e., multiple crosses) is being used widely to improve QTL characterization for traits of agricultural value (see, for example, Christiansen et al.
However, mating success clearly decreased in the F@ intercrosses
(3.3% and 13.3%) and in the backcrosses (7.7-40%).
Frequency distributions of the disease severity of [F.sub.2] plants and [F.sub.5] lines of the resistant parent intercrosses
were used to study the similarity of segregating factors.
in press) show that in crosses derived from other inbred strains, the genes associated with alcohol phenotypes are different from those detected in the B6xD2 intercrosses
. Thus, the possibility still remains that in some crosses, preference and anxiety may be related.
Sells and intercrosses
of short internode plants bred true.
To investigate allelism, all possible intercrosses
between the six mutants and BW755 (Grandin[sup.*]3/Fidel-FS-4) were made.
of the best-performing plants were subjected to varying cycles of population improvement, which included both phenotypic and genotypic selection, combined with occasional population backcrossing.
Progenies resulting from intercrosses
of the best performing clones were evaluated in single-plant progeny tests maintained as closely mowed turf plots.
On the basis of segregation patterns in the [F.sub.1] of intercrosses
, Sasakuma (1978) concluded that mutations in FS2, FS3, and FS24 were allelic, but the FS20 mutant was nonallelic to the other mutations.
Progenies of intercrosses
among the best performing plants were subjected to varying numbers of cycles of phenotypic and genotypic selection, depending on their date of collection.
of selected plants were subjected to varying numbers of cycles of phenotypic and genotypic recurrent selection in mowed clonal evaluation tests, spaced-plant nurseries, greenhouse trials, and single-plant progeny tests conducted under turf maintenance conditions.
of the best ryegrasses were subsequently used to initiate population improvement programs that involved varying numbers of cycles of phenotypic and genotypic recurrent selection in spaced-plant nurseries, disease screening under greenhouse conditions, and progeny evaluation in closely mowed turf trials.