Commercial hybrid wheat seed has been produced using chemical hybridizing agents; these chemicals selectively interfere with pollen development, or naturally occurring cytoplasmic male sterility systems.
22.
Cytoplasmic male sterility genes, usually found in the mitochondrial genome, show up and are established when female fertility is just slightly more than the hermaphroditic fertility.
23.
Incorporation of these systems for male sterility evades the need for emasculation in cross-pollinated species, thus encouraging cross breeding producing only hybrid seeds under natural conditions.
24.
In plants, barriers to hybridization include blooming period differences, different pollinator vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and structural differences of the chromosomes.
25.
Zeng's company, Changshou Changle ( Long Life, Long Happiness ), produces the successful Tonic Juice of Longevity and other traditional medicines, such as an herbal treatment for male sterility.
26.
About 15 % of the corn crop was lost to infection and for the next few years male sterility was abandoned and nearly all seed corn was again detasseled manually.
27.
The EPA, not surprisingly, has found toxic chemicals in the fat cells of every person they studied, and scientists now suspect that pesticides play a significant role in the rising rate of male sterility.
28.
Contraceptive measures that lead to male sterility, are not ever permitted for their interfering with a man's obligation, only ever being permitted in life-threatening circumstances for the man such as some forms of cancer.
29.
Cytoplasmic & ndash; genetic male sterility systems are widely exploited in crop plants for hybrid breeding due to the convenience of controlling sterility expression by manipulating the gene & ndash; cytoplasm combinations in any selected genotype.
30.
The sex-lethal gene is often abnormally expressed in male hybrids from " D . melanogaster " mothers as a result of re-localization of the male-specific complex to the X chromosome, which contributes to the male sterility.
