Reciprocal Full‐Sib Recurent Selection in Maize: I. Direct and Indirect Responses

Abstract

Interpopulation recurrent selection methods can be used for developing new heterotic patterns and enhancing those identified previously. The objective of this research was to estimate the direct and indirect responses to eight cycles of reciprocal full‐sib recurrent selection in maize (Zea mays L.) populations BS10 and BS11. The populations and their crosses corresponding to Cycles 0, 2, 4,6, and 8 were evaluated at two levels of inbreeding (F = 0 and F = 0.5), and populations also were testcrossed to the respective Cycle 0 populations and unrelated inbred lines. Entries were evaluated in eight environments. Eight cycles of selection were effective for increasing grain yield of the population cross (6.5% cycle−1), BS10 (3.0% cycle−1), and BS11 (1.6% cycle−1). Standability, prolificacy, and grain moisture also were changed in the desired directions, and, in most instances, the responses were linear across cycles of selection. Direct responses were greater than indirect responses for grain yield and Standability. The selected populations also performed better than did the unselected populations in crosses with unrelated testers. Changes in inbreeding depression and heterosis were associated with selection. Rates of direct and indirect responses for grain yield in the inbred populations tended to be greater than the rates of responses in the noninbred populations. Reciprocal full‐sib selection increased the frequency of homozygotes for favorable alleles in the BS10 and BS11 populations, which would be improved sources of vigorous inbred lines with good general combining ability. Reciprocal full‐sib selection seems to have increased the frequency of heterozygotes in the population crosses.

Progresso genético com a seleção recorrente recíproca para híbridos interpopulacionais de milho

“…Trabalhos com populações derivadas de híbridos simples mostraram respostas de 5,7 (Raposo et al, 2004), 4,5 e 6,2% (Coors, 1999) à seleção por ciclo. Em programas com populações temperadas (BS10 e BS11) submetidas à SRR de irmãos germanos por oito ciclos, Eyherabide & Hallauer (1991) reportaram ganho de 6,5% por ciclo. Keeratinijakal & Lamkey (1993), ao trabalhar com as populações BSSS e BSBC1 por 11 ciclos, relataram ganho de 6,95% com a seleção por ciclo.…”

Seleção e herdabilidade na predição de ganhos genéticos em maracujá-amarelo

“…O esquema de famílias deste delineamento, freqüentemente utilizado na cultura do milho (Hallauer & Miranda Filho, 1988;Eyherabide & Hallauer, 1991;Furtado, 1996), permite adotar diferentes estraté-gias de seleção, tais como: seleção entre machos, fê-meas, fêmeas hierarquizadas a machos e seleção combinada (Cruz & Carneiro, 2003).…”

Performance of maize single-crosses developed from populations improved by a modified reciprocal recurrent selection

“…One cycle of the modified (MRRS) procedure designed by Rezende and Souza Jr. (2000) increased grain yield by 16.7% and reduced significantly plant and ear heights. In a per cycle basis, this MRRS procedure increased grain yield at a higher rate than the 6.0% to 7.0% reported for standard RRS programs where 10% to 20% as selection intensity and S 1 lines for recombination were used (Eyherabide and Hallauer, 1991;Santos et al, 2007;Santos et al, 2005;Souza Jr. and Pinto, 2000). Then, the MRRS procedure was highly effective in improving the population cross performance in only one cycle of selection.…”

“…Reciprocal recurrent selection (RRS) is a long-term cyclical breeding procedure outlined to improve population crosses, and reported results have shown that RRS has been very effective (Eyherabide and Hallauer, 1991;Souza Jr. and Pinto, 2000;Santos et al, 2005), and also the improved populations have been sources of elite inbreds and outstanding single-crosses Betrán and Hallauer, 1996). The elite inbred lines from the RRS programs are unrelated to the inbreds developed from the recycling programs, and then they could be incorporated to these programs to maintain the rate of the development and release of new hybrids.…”