No abstract

Seeds of hexaploid wheat variety Chinese Spring were treated with ethyl methanesulfonate (EMS). Two hundred and fifty-six plants were observed in the M1 generation which had white, yellow or pale green longitudinal stripes in their leaves. Of four recessive, viable, simply inherited chlorophyll mutations obtained in M2, two were chlorina (pale yellow-green), one was virescent (white or nearly white as a seedling but later turning green), and one was also virescent but in some plantings had late leaves that were 'white banded'. An albino mutation was also recovered.The two chlorina mutants were located on chromosomes 7B and 7D, the homoeologues of chromosome 7A, which was already known to carry a similar mutation, chlorina-1. The mutants were located by the use of monosomics, taking advantage of the fact that when the chromosome carrying a chlorina gene was made monosomic, segregation of the gene then depended upon the male and female transmission of the monosome, with the result that all disomic offspring, and no others, were chlorina. Monosomic analysis also indicated that the viridis (white or nearly white as a seedling but later turning green) mutation is located on chromosome 3A, which was already known to carry a homoeologue of the normal allele of the gene determining a similar mutation, Neatby's virescent, on chromosome 3B.In crosses, similar mutants complemented each other only partially or not at all, showing that the mutant genes are functionally similar, although located on different chromosomes.

For the detection of low amniotic fluid volumes, the AFI to the cord is better than through the cord. Measurement to the cord and through the cord had similar accuracy for both the AFI and SDP techniques in normal and high dye-determined amniotic fluid volumes.

Alloplasmic lines of Triticum aestivum L. em. Thell. ‘Chris’ and ‘Selkirk’ and T. durum Desf. Sel. 56‐1 were tested to three individual physiologic races of wheat leaf rust (Puccinia recondita Rob. ex. Desm. f. sp. tritici) at the seedling and adult plant stages. Chris was resistant at the adult stage but susceptible at the seedling stage to all three races used. However, alloplasmic Chris lines with the cytoplasm of T. araraticum Jakubz., T. timopheevi Zhuk., T. macha Des. & Men., T. boeoticum Boiss., Aegilops ovata L., or Ae. speltoides Taush. were susceptible or moderately susceptible at the adult stage to one or more of the rust races. Selkirk and alloplasmic Selkirk lines with the cytoplasms of these and several other species were resistant at the seedling and adult plant stage to the three races. T. durum Sel. 56‐1 and alloplasmic durum lines had mesothetic reactions to the three races, and rate of uredial development was slower on alloplasmic durum lines than on the controls. Apparently, certain alien cytoplasms influence the expression of genes for resistance to certain races of wheat leaf rust.