How Many Parents Give the Highest Yield in Predicted Synthetic and Composite Populations of Maize?

Kutka, Frank; Smith, Margaret E.

doi:10.2135/cropsci2006.12.0802sc

Cited by 20 publications

(16 citation statements)

References 41 publications

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“…The application of Wright's equation to historical data on maize inbreds and hybrids suggests the possibility of synthetics that yield more than 90% of commercial hybrids if the research were carried out (Table 3), although the work would be intensive with many questions to be answered [36,141,150]. Might such diverse populations open up new ways of dealing with diseases and pests as has worked for multilines of rice [151]?…”

Section: Composite and Synthetic Populations As Op Cultivarsmentioning

confidence: 99%

Open-Pollinated vs. Hybrid Maize Cultivars

Kutka¹

2011

Sustainability

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Abstract:The history of maize breeding methods in the USA is reviewed to examine the question of types of maize cultivars in sustainable agriculture. The yield potential of OP cultivars was much higher than national average yields prior to 1930, but hybrid cultivars today often out-yield OP cultivars by 50-100% or more. However, rates of gain for yield using recurrent selection on populations appear equal to that recorded for commercial hybrid breeding. The inbred-hybrid method, while successful, was not "the only sound basis" for maize improvement, as evidenced by later experiences in the United States and worldwide. It appears that maize breeders have practiced objective science and achieved concrete goals, although personal interests and goals clearly direct the work at times. As society looks for tools for sustainability based on achieving multiple goals, a special dedication to scientific validation and broad objectivity may be required. The potential for OP cultivars today is evaluated and research questions are identified.

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Section: Composite and Synthetic Populations As Op Cultivarsmentioning

confidence: 99%

Open-Pollinated vs. Hybrid Maize Cultivars

Kutka¹

2011

Sustainability

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“…First, COPOP1 is an open-pollinated population that was compared to four commercial hybrids. Grain yield of open-pollinated cultivars is expected to be about 70% of that of a hybrid (Kutka and Smith, 2007). Therefore, if suffi cient heterosis exists within COPOP1, we could expect a yield increase from the development of hybrids from COPOP1-derived inbreds.…”

Section: Copop1 Semidwarf Corn For Grain Productionmentioning

confidence: 99%

“…First, COPOP1 can be used as an open-pollinated cultivar. In recent years, there has been a renewed interest from public breeders in developing improved populations and population hybrids as an alternative to single-cross hybrids (Kutka and Smith, 2007;Carena, 2005). As previously mentioned, COPOP1 will be most useful in very Table 6.…”

Section: Future Utilization Of Semidwarf Cornmentioning

confidence: 99%

Breeding Potential of Semidwarf Corn for Grain and Forage in the Northern U.S. Corn Belt

Schaefer

Bernardo

2011

Crop Science

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Conventional, nondwarf corn {Zea mays L.) hybrids grown in the northern U.S. Corn Belt are typically >2 m tall and have a 75-to 100-d relative maturity (RM). Our objectives were to assess the potential of open-poHinated C0P0P1 semidwarf corn for grain and forage production, estimate genetic variances and heritability in C0P0P1, and develop COPOP1 subpopulations that exhibit heterosis. In 2005 and 2006, we evaluated C0P0P1 with four commercial, nondwarf hybrids at three plant population densities. Grain yield of open-pollinated COPOP1 was about half of the mean yieid of the conventionai hybrids. However, C0P0P1 had lower grain moisture (equivalent to 62 d RM) and better forage quality than the commercial hybrids. In 2007, C0P0P1 was evaluated for performance when crossed to two divergent inbred testers, LH227 and LH295. Heritability was significant for grain moisture, plant height, and ear height in testcrosses to both testers but was significant for grain yield only in testcrosses to LH227. In 2009, bulk Cycle 0 (i.e., original C0P0P1) and Cycle 1 testcrosses, nine semidwarf hybrids, C0P0P1, and three commercial hybrids were evaluated at two plant population densities. Grain yieid and most agronomic and forage traits did not improve between Cycle 0 and Cycle 1 in either testcross population. None of the semidwarf hybrids had higher grain yieids than C0P0P1. While semidwarf C0P0P1 can serve as a souroe of useful variation for improving elite germplasm in the northern U.S. Corn Beit, further selection in C0P0P1 must be done to deveiop improved semidwarf populations. Abbreviations: ASI, anthesis-silking interval; BSSS, Iowa Stiff Stalk Synthetic; IVTD, in vitro true digestibility; NDF, neutral detergent fiber; NDFD, neutral detergent fiber digestibility; NIRS, near-infrared reflectance spectroscopy; RM, relative maturity. I N CORN {Zea mays L.), genes such as reduced plant 1 {rdl), brachytic 2 {br2), and compact plant {ci) cause dwarfing (Nelson and Ohlrogge, 1957;Scott and Campbell, 1969;Modarres et al., 1997b;Neuffer et al., 1997). Semidwarf corn may have characteristics that make it suitable for grain and forage production in short-season environments (Dijak et al., 1999;Coors and Lauer, 2001). In particular, the limited heat units in short-season environments reduce grain yield and lessen the probability of the crop reaching physiological maturity in a given year. Semidwarf hybrids have required 10% fewer heat units than conventional hybrids to reach anthesis (Dijak et al., 1999) and generally reach physiological maturity earlier than conventional cultivars (Modarres et al., 1997a). Like semidwarf wheat {Triticum aestivum L.; Vogel et al., 1963), semidwarf sorghum {Sorghum bicolor L.; Windscheffel et al., 1973), and semidwarf rice {Oryza sativa L.; Hedden, 2003), semidwarf corn may be less prone to stalk and root lodging due to the shorter stalks and lower ear placement (Dijak et al., 1999). Semidwarf corn has the potential to produce high-quality forage due to its high ear-to-stover ratio, although dry matter y...

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“…Additionally, inbred lines from the North American Corn Belt did not demonstrate potential for enhanced stover yield and quality when compared with inbred lines from Argentine germplasm (Bertoia et al 2002). According to Vencovsky andMiranda Filho (1972), Miranda Filho (1974), Rodrigues and Chaves (2002), Oliveira et al (2006), Kutka and Smith (2007), composites are appropriate for use as base populations in breeding programs. Composites are obtained by intercrossing two or more open pollinated varieties with the objective of obtaining a new population with high genetic variability (and a high mean for the traits of interest).…”

Section: Introductionmentioning

confidence: 99%