Identification of a third fuzzless seed locus in upland cotton (Gossypium hirsutum L.).

Segregating populations were developed to evaluate the inheritance of the fuzzless seed phenotypes in upland cotton (Gossypium hirsutum L.). Accession 143 of the Mississippi Obsolete Variety Collection (MOVC) has a fuzzless seed phenotype. This line carries the n(2) locus which is recessive to the seed fuzz phenotype. Data from the F(2), BC(1)F(1), F(2:3), and BC(1)F(2) populations of DP 5690 x 143 fit a two-loci model for expression of the recessive fuzzless seed phenotype. Fuzzless seeds were obtained in n(2)n(2) plants when a second recessive locus (n(3)) was present. The dominant N(3) allele found in DP 5690 confers the fuzzy seed phenotype in homozygous n(2) plants. Accession 243 of the MOVC carries the N(1) locus, which is dominant to the presence of seed coat fuzz. No variation from expected ratios was observed in the F(2), BC(1)F(1), F(2:3), and BC(1)F(2) populations of the DP 5690 x 243 cross. The N(3) allele had no apparent effect on the expression of the N(1) locus. In a cross between accessions 243 x 143, a few plants were observed which were completely devoid of lint and fuzz fiber (fiberless). A fiberless line was developed from one of these fiberless plants. This line was designated MD 17 fiberless. In a cross between DP 5690 x MD 17 fiberless, we demonstrated that at least three loci were involved in the expression of the fiberless phenotype. The involvement of n(2) and n(3) in the expression of this fiberless phenotype was demonstrated in the F(2) progeny of the cross between 143 x MD 17 fiberless. This is the first demonstration that N(1), n(2), and n(3) interacted to produce fiberless seed.

Small-dose droperidol effectively reduces nausea in a general surgical adult patient population.

UNLABELLED: In this prospective, randomized, placebo-controlled study, we (1) determined whether 0.625 mg of IV droperidol given 30 min before emergence from general anesthesia reduces the incidence of immediate and delayed postoperative nausea and vomiting (PONV) in a general surgical adult patient population, and (2) compared the efficacy of droperidol, ondansetron, and promethazine for the rescue treatment of PONV. One hundred fifty adult patients receiving general anesthesia for >2 h received either droperidol (0.625 mg IV) or a placebo before emergence. Patients requiring treatment for PONV in the postanesthesia care unit were randomized to receive either droperidol (0.625 mg IV), ondansetron (4 mg IV), or promethazine (12. 5 mg IV). Droperidol effectively prevented PONV (6.8% in droperidol-treated patients versus 40.8% in placebo-treated patients, P: < 0.001). Droperidol, ondansetron, and promethazine were equally effective in treating established PONV, without significant differences in side effects or time to postanesthesia care unit discharge. IMPLICATIONS: Droperidol 0.625 mg IV before emergence from general anesthesia effectively reduces postoperative nausea and vomiting (PONV) in the general surgical population. Our randomized, double-blinded, placebo-controlled study demonstrated a reduction in PONV from 41% to 7%. Droperidol is a safe and inexpensive alternative to ondansetron. Droperidol, ondansetron, and promethazine are also equally effective in treating PONV in the postanesthesia care unit.

Identification of a delta-TIP cDNA clone and determination of related A and D genome subfamilies in Gossypium species.

Tonoplast intrinsic proteins (TIPs) have been implicated in the process of cell elongation, such as occurs in the developing cotton fiber. We have isolated a cDNA clone (997 bp in length) from a cotton (Gossypium hirsutum L.) library which putatively encodes a protein of 248 residues (Mr 25079) with 85% identity to Arabidopsis delta-TIP. The derived amino acid sequence included two conserved sequences associated with major intrinsic proteins (SGxHxNPA at residues 78 to 85, NPA residues at 197 to 199) and a cysteine residue at 116 which is reported to bind mercury in Arabidopsis delta-TIP. The polymerase chain reaction was used to generate partial genomic clones of the cotton delta-TIP. In comparison to other genomic TIP sequences, the number (two) and position of the introns were conserved in cotton. Comparing the TIP sequences from cotton revealed two subfamilies, which were consistently distinguished by a Tsp45I restriction site polymorphism. This polymorphism was used to demonstrate that TIP subfamilies were specific to either the A or D genomes of Gossypium. When delta-TIP DNA fragments were amplified from cDNA of fiber 14 days after anthesis, the A and D were found, indicating the presence of delta-TIP transcripts in these elongating cells.

Quantitative trait loci affecting cotton fiber are linked to the t1 locus in upland cotton.

Pilose (T 1), a dominant marker in upland cotton, has been associated with coarse, short fibers. Pilose was, thereby, considered to be pleiotropic on fiber fineness and length. However, a pilose-expressing line with a fiber of average fineness was recently identified. This finding does not support pleiotropy between T 1 and fiber traits, but is indicative of linkage between pilose and loci influencing fiber characteristics. To understand the relationship between T 1 and fiber traits, a pilose line with short, coarse fiber was crossed to two t 1 lines with standard fiber characteristics. One hundred and forty-nine F2-derived F3 lines were developed from one cross, and 60 F2-derived F3 lines from the other. Seven fiber traits (elongation, maturity, micronaire reading, perimeter, 2.5% span length, strength, and wall thickness) were measured. Segregation was normal, as indicated by allelic frequencies of 0.5 for T 1 and t 1, and segregation ratios of 1∶2∶1 for marker genotypes. The association of homozygous T 1 lines with fibers of average fineness was again observed. Linkage between T 1 and loci affecting micronaire, perimeter, 2.5% span length, strength, and wall thickness was found in both populations. Significant additive and non-additive gene effects for each of these traits at the marker locus were found as well. The pilose marker accounted for 10-75% of the phenotypic variation associated with each trait. In conclusion, the t 1 locus is linked to numerous loci that influence fiber traits, and this linkage has previously been misinterpreted as pleiotropy.

The inheritance of a urease-null trait in soybeans.

Four soybean seed urease nulls (lacking both the activity and antigen of the embryo-specific urease) were intermated and the F1 and F2 seed examined for urease activity. Both generations were without urease activity, and the nulls were therefore considered noncomplementing. In crosses of each null line to cultivars homozygous for the allelic, codominantly inherited urease slow or fast isozyme, the F1 seed expressed the embryo-specific urease isozyme of the urease-expressing parent. A 3 ∶ 1 segregation for presence and absence of urease was observed in progeny from F1 and heterozygous F2 plants. The F2 and F3 from fastXnull combinations revealed that urease-positive seed were all phenotypically urease fast, while the same seed from slowXnull combinations showed a segregation of one seed containing a fast urease, either exclusively or in a heterozygous state with the slow isozyme, for every 69 phenotypic slows. Data pooled from F2 plants which segregate for both the presence (Sun) and absence (Sun) of urease and for the fast (Eu1-b) or slow (Eu1-a) urease allele indicate that the null lesion (Sun) is linked to Eu1 by approximately one map unit. The evidence is consistent with two models: (1) sun is an allele at the embryo-specific urease isozyme locus (Eu1) and that a high degree of exchange (and/or conversion) within the locus results in a 1% recombination frequency between the null trait and urease allozyme; (2) sun is at a distinct locus which is separated by one map unit from the embryo-specific urease isozyme locus (Eu1) upon which it acts in the cis position. Polyadenylated embryo RNA from one of the null lines, PI 229324, exhibited no urease template activity in vitro. Thus, the lack of urease antigen is due to lack of accumulation of translatable urease mRNA. The availability of soybeans lacking seed urease should be extremely useful to breeders as a trait for linkage studies and to geneticists as a transformation marker.