This invention describes a new method to increase grain yields in any crop plant by modifying pollination to effect an increase in grain yield, a change in grain content or characteristics, a decrease in contamination, or a combination of these attributes. The process involves the intentional delivery of pollen of the male plant at will to designated male-sterile female plants as available either in a preserved pollen bank, or real-time collection from male plants as they become available, in a growth chamber for example. Desired pollen is delivered to fertile females. The delivered pollen.sup.M is in such amounts and fortuitously timed that it preferentially pollinates the females and pollination from neighboring male-fertile plants. The intentional delivery of genetically different pollen will result in increased heterosis and accompanying grain yield increases resulting from increased grain size and the potential to influence grain content and constituents. The invention also permits real-time agronomic decision making in order to maximize grain yield by overcoming biotic and abiotic challenges in the growing season which may or may not have been anticipated.

A method for breeding polyploid two-line hybrid rice includes determining a tetraploid rice photo thermosensitive genic male sterile line with the gene characteristic of PMeS (polyploid meiosis stability) and a tetraploid rice restoring line with the gene characteristic of PMeS; hybridizing and matching by indica sterile/japonica restoring or japonica sterile/indica restoring hybrid combination; preparing a tetraploid rice hybrid by adopting a tetraploid rice photo thermosensitive genic male sterile line and a tetraploid rice restoring line; and breeding a stable tetraploid rice hybrid combination which is determined as the polyploid two-line hybrid rice combination. The breeding method disclosed by the present invention utilizes the strong heterosis of polyploid rice, and transforms the existing diploid heterosis into the heterosis of polyploid two-line hybrid rice; and by adopting the method disclosed by the present invention, a new polyploid two-line hybrid rice variety with large ears, large grains and high yield can be bred.

The present invention relates to non-transgenic and transgenic plants, preferably crop plants, having biological activity of a haploid inducer and comprising a polynucleotide which comprises a nucleotide sequence encoding a centromer histone H3 (CENH3) protein, wherein the polynucleotide comprises at least one mutation causing an alteration of the amino acid sequence of the CENH3 protein, and to a part of the part. Further, the invention provides methods of generating the inducer plants, methods of generating haploid and double haploid plants using the inducer plants as well as methods of facilitating cytoplasm exchange.

This invention describes a new method to generate wheat seed. The process involves the delivery of pollen of the male parent at will, as available either in a preserved pollen bank, or using real-time collection from male plants as they become available. Desired pollen is delivered to fertile females during the period when viable pollen from the females and locally proximal unrelated plants is not being released. The delivered male pollen is in such amounts and fortuitously timed that it preferentially pollinates the females. Such fortuitous timing may involve the intentional application of pollen to females a day or two prior to female parent pollen becoming viable, and/or during several periods wherein female parent pollen and/or other proximal plant pollen is not being shed.

The present invention provides use of a photoperiod-sensitive genic male sterility mutant of cotton in crossbreeding or hybrid seed production. The fertility of the photoperiod-sensitive genic male sterility mutant of cotton is influenced by the photoperiod. The photoperiod characteristic of the photoperiod-sensitive genic male sterility mutant of cotton is that, the photoperiod-sensitive genic male sterility mutant of cotton shows normal fertility when the illumination time is shorter than 11.5 h and shows genic male sterility when the illumination time is longer than 12 h; the photoperiod-sensitive genic male sterility mutant of cotton is in a fertility change period when the illumination time is in a range of 11.5-12 h and has less pollen. The photoperiod-sensitive genic male sterility mutant of cotton is PSM1, and/or a photoperiod-sensitive genic sterile line obtained through selective breeding of hybridized and/or backcrossed and/or self-bred offsprings of the PSM1.

This invention describes a new method to generate wheat seed. The process involves the delivery of pollen of the male parent at will, as available either in a preserved pollen bank, or using real-time collection from male plants as they become available. Desired pollen is delivered to fertile females during the period when viable pollen from the females and locally proximal unrelated plants is not being released. The delivered male pollen is in such amounts and fortuitously timed that it preferentially pollinates the females. Such fortuitous timing may involve the intentional application of pollen to females a day or two prior to female parent pollen becoming viable, and/or during several periods wherein female parent pollen and/or other proximal plant pollen is not being shed.

This invention describes a new method to generate hybrid seed in any crop plant while also reducing contamination from out-crossings and self-pollination. In contrast to conventional seed production methods, the method of the invention is not dependent on the use of any form of male sterility in the female parent plants, nor the use of isolation distances from unrelated and undesirable plants of the same species, nor the use of male parent plants in proximity to the targeted females. The process involves the delivery of pollen of the male parent at will, as available either in a preserved pollen bank, or using real-time collection from male plants as they become available. Desired pollen is delivered to fertile females during the period when viable pollen from the females and locally proximal unrelated plants is not being released. The delivered male pollen is in such amounts and fortuitously timed that it preferentially pollinates the females and produces relatively pure hybrid seed at levels much higher than if one used current hybrid production practices and did not utilize male sterility practices or prescribed isolation distances. Such fortuitous timing may involve the intentional application of pollen to females a day or two prior to female parent pollen becoming viable, and/or several consecutive mornings prior to female parent pollen or other proximal plant pollen beginning to shed each day.

Methods are described for selecting or producing a cereal plant comprising a functional restorer gene for wheat G-type cytoplasmic male sterility and nucleic acids and/or polypeptides for use therein.

Various methods and compositions are provided for identifying and/or selecting a sorghum plant or germplasm with or without a cytoplasmic male sterility (CMS) trait. In certain embodiments, the method comprises detecting at least one allele of one or more marker locus within or linked to a QTL associated with CMS. In further embodiments, the method comprises crossing a selected sorghum plant with a recurrent sorghum parent plant and selecting progeny with CMS.

A breeding method of a polyploid rice photo-thermo-sensitive genetic male sterile line includes determining a diploid rice line with photo-thermo-sensitive genetic male sterility or PMeS characteristic as a parent; carrying out hybridization on a diploid photo-thermo-sensitive genetic male sterile line and a diploid PMeS gene line, carrying out doubling culture on a young ear of a hybrid plant into a hybrid tetraploid; back-crossing the hybrid tetraploid with a tetraploid photo-thermo-sensitive genetic male sterile line; selecting a tetraploid male sterile plants from the back-crossed progeny, self-crossing during a low-temperature and short-day fertile period, and then carrying out composite hybridization with another tetraploid rice line having PMeS gene; selecting tetraploid male sterile plants, and detecting the stability of tetraploid male sterile plants after multiple generations of continuous self-crossing; and determining the stable and consistent tetraploid rice sterile line as the polyploid rice photo-thermo-sensitive genetic male sterile line, named as PSXXX.