MODERN MAIZE HYBRIDS CAN IMPROVE GRAIN YIELD AS PLUS-HYBRIDS BY THE COMBINED EFFECTS OF CYTOPLASMIC MALE STERILITY AND ALLO-POLLINATION

A cytoplasmic male-sterile (CMS) maize (Zea mays L.) hybrid is referred to as a Plus-Hybrid when it is grown in mixture with an unrelated pollinator, i.e. when it is allo-pollinated. It often leads to higher grain yields than the corresponding sib-pollinated male-fertile hybrid. To improve breeding processes, more knowledge of Plus- Hybrid effects with modern plant material must be ac- quired. The Plus-Hybrid abilities of 12 modern European hybrids from diverse breeders, representing all three types of CMS, were evaluated in a field study at three lo- cations in Switzerland in 2005; their suitability as pollen receptors and pollen donors were tested by combining their male-sterile and male-fertile forms with two respec- tive known tester hybrids. The variations caused by the CMS effect on the yield of a specific genotype in a given environment ranged from -8 to +8%. These variations did not depend on the type of male-sterile cytoplasm. The Plus-Hybrid effect for a specific combination was consis- tent among locations, but the extent of the effect depend- ed on the environment. The test pollinator induced an av- erage Plus-Hybrid effect of +6.9% on the grain yield of the set of CMS hybrids. After allo-pollination, the yield of seven of the 12 CMS hybrids increased by more than +8% (mainly due to a higher thousand kernel weight). Al- though the impact of the type of cytoplasm was not sig- nificant, hybrids with C and T cytoplasm showed a stronger response to allo-pollination than hybrids with S cytoplasm. Five very responsive CMS hybrids and one good pollinator, originating from different European breeders, were identified among the set of 12 hybrids tested in these field trials.

[1]  M. E. Otegui,et al.  Ovary Growth and Maize Kernel Set , 2007 .

[2]  R. Shibles,et al.  Pollination Timing Effects on Kernel Set and Silk Receptivity in Four Maize Hybrids , 2004 .

[3]  J. I. Lizaso,et al.  Quantitative Relationships between Pollen Shed Density and Grain Yield in Maize , 2003 .

[4]  P. Stamp,et al.  Combining Cytoplasmic Male Sterility and Xenia Increases Grain Yield of Maize Hybrids , 2002 .

[5]  P. Stamp,et al.  A PCR Assay for Rapid Discrimination of Sterile Cytoplasm Types in Maize , 2002 .

[6]  P. Stamp,et al.  The plus-hybrid system: A method to increase grain yield by combined cytoplasmic male sterility and xenia , 2002 .

[7]  M. E. Otegui,et al.  Ear temperature and pollination timing effects on maize kernel set , 2001 .

[8]  P. Stamp,et al.  Increase in the Yield of Cytoplasmic Male Sterile Maize Revisited , 2000 .

[9]  Mark E. Westgate,et al.  Synchronous pollination within and between ears improves kernel set in maize , 2000 .

[10]  J. Prioul,et al.  Xenia effects in maize with normal endosperm: II. Kernel growth and enzyme activities during grain filling. , 2000 .

[11]  A. Gallais,et al.  Xenia effects in maize with normal endosperm: I. Importance and stability , 1998 .

[12]  P. Schnable,et al.  The molecular basis of cytoplasmic male sterility and fertility restoration , 1998 .

[13]  R. Lambert,et al.  Pollen Parent Effects on Oil, Protein, and Starch Concentration in Maize Kernels , 1998 .

[14]  D. Seka,et al.  Xenia and maternal effects on maize kernel development , 1995 .

[15]  P. Bassetti,et al.  Floral asynchrony and kernel set in maize quantified by image analysis , 1994 .

[16]  C. S. Levings.  Thoughts on Cytoplasmic Male Sterility in cms-T Maize. , 1993, The Plant cell.

[17]  R. Weiland.  Cross-pollination effects on maize (Zea mays L.) hybrid yields , 1992 .

[18]  C. Tsai,et al.  Effects of cross‐pollination on dry matter accumulation, nutrient partitioning and grain yield of maize hybrids grown under different levels of N fertility , 1991 .

[19]  Fritz Bangerth,et al.  Dominance among fruits/sinks and the search for a correlative signal , 1989 .

[20]  B. Christie,et al.  Grain yield comparison of pure stands and equal proportion mixtures for seven hybrids of maize , 1985 .

[21]  D. Smith,et al.  Comparative Grain Yields of Corn Hybrids in Normal and in Texas Male‐Sterile Cytoplasm (cms‐T) Infected with Helminthosporium maydis Race T and Disease Components of cms‐T Corn Hybrids 1 , 1974 .

[22]  D. Duvick.  Cytoplasmic Pollen Sterility in Corn , 1965 .

[23]  H. L. Everett.  Effect of cytoplasms and an Rf gene in maize. , 1960 .

[24]  J. S. Rogers,et al.  The Utilization of Cytoplasmic Male‐Sterile Inbreds in the Production of Corn Hybrids1 , 1952 .