Response of Corn (Zea maysL.) Inbreds and Hybrids to Sulfonylurea Herbicides

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 508-516 ◽  
Author(s):  
Jerry M. Green ◽  
Jim F. Ulrich

Extensive field and greenhouse studies were done to characterize varietal response of three recently commercialized sulfonylurea corn herbicides: nicosulfuron, primisulfuron, and thifensulfuron. Most of the 94 varieties tested were highly tolerant to these herbicides. The 37 inbreds represented all major inbred families now used in hybrid seed production as well as several sensitive experimentals. Twenty-one defined hybrids from these inbreds as well as 36 commercially coded hybrids were also tested. Sensitive inbreds produced tolerant hybrids when crossed with tolerant inbreds. Sensitive hybrids occurred when both parents were sensitive. Genetic analysis of sensitive by tolerant crosses showed that sensitivity is controlled by a single recessive gene. Nicosulfuron had the widest corn safety margin and fewest sensitive varieties. Dose response analysis showed varieties can vary more than 40 000-fold in sensitivity. Only corn varieties with the AHAS-modified XA-17 gene showed any change in enzyme sensitivity. This gene overcame sensitivity to sulfonylureas, even when the organophosphate insecticide terbufos was present. Thus, breeders have three options to eliminate sulfonylurea sensitivity: backcross sensitive inbreds with tolerant, always use at least one tolerant hybrid parent, or use the XA-17 gene.

1994 ◽  
Vol 119 (5) ◽  
pp. 1054-1056 ◽  
Author(s):  
Richard L. Fery ◽  
Philip D. Dukes

A series of greenhouse and field studies were conducted to determine the inheritance of the green cotyledon trait exhibited by the recently released southernpea `Bettergreen' and to elucidate the genetic relationship between the green cotyledon trait and the green testa trait exhibited by `Freezegreen'. Evaluation of parental, F1, F2, and backcross populations of the crosses `Bettergreen' × `Carolina Cream' and `Bettergreen' × `Kiawah' indicated that the green cotyledon trait is conditioned by a single recessive gene. Evaluation of parental and F2 populations of the cross `Bettergreen' × `Freezegreen' indicated that this gene is neither allelic to nor linked with the gt gene that conditions the green testa trait in `Freezegreen'. The color of seeds harvested from plants homozygous for both the green cotyledon and green testa genes was superior and more uniform than the color of seeds harvested from either `Bettergreen' or `Freezegreen' plants. We propose that the newly discovered gene be designated green cotyledon and symbolized gc. Seeds containing embryos homozygous for the gc gene are easily identified. The ability to select in the seed stage should greatly facilitate efforts to backcross the gc gene into cream-, pinkeye-, and blackeye-type cultivars.


Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 295-311
Author(s):  
P W Becraft ◽  
M Freeling

Abstract Maize Rough sheath1 (Rs1) mutants are dominant and cause a proliferation of sheath-like tissue at the base of the blade and throughout the ligular region. They also cause ligule displacement, a chaotic pattern of vasculature and abnormal cellular structure of vascular bundles. The affected region of Rs1-O leaves displays genetic and morphological attributes of both sheath and auricle, suggesting an overlap of these genetic programs. The rs1 locus maps approximately 26 map units distal to opaque2 (o2) on chromosome 7S, defining a new distal-most locus on the genetic map. Three mutant alleles, Rs1-O, Rs1-1025 and Rs1-Z, all display similar phenotypes. The mutations are completely dominant and the Rs1-O phenotype is not affected by dosage of the chromosome arm carrying the rs1+ allele, indicating that these alleles are neomorphic. Analysis of genetic mosaics showed that the Rs1-O phenotype is non-cell-autonomous, suggesting that intercellular signals convey the phenotype. Rs1 mutant phenotypes are affected by modifiers present in particular genetic backgrounds. An enhancer of Rs1-O was identified; segregation data imply a single recessive gene, ers1. Rs1 mutants were also found to enhance the expression of unlinked rs2 and Rs4 mutants, suggesting that these mutations affect similar developmental processes. We discuss the phenotypic and genetic similarities between Rs1 and Knotted 1 (Kn1) mutants that led to the identification of rs1 as a kn1-like homeobox gene (unpublished data).


1969 ◽  
Vol 11 (1) ◽  
pp. 30-33
Author(s):  
B. P. Goplen

A genetic analysis of P1, F1, F2 and BC1 in Melilotus alba revealed that the pale cotyledon trait was controlled by a single recessive gene, designated pc. This trait is characterized by chlorophyll-deficient cotyledons and normal green unifoliolate and subsequent trifoliolate leaves. Mature plants are indistinguishable from normal green sibs. The consistent deficiency of recessive F2 segregates was attributed to reduced vigor and differential seedling survival of the pale cotyledon segregates.


Zuriat ◽  
2015 ◽  
Vol 3 (1) ◽  
Author(s):  
, Mugiono

Rice breeding using induced mutation has succesfully produced several mutant lines resistant to brown planthopper. In order to beable to utilize these mutant lines further in a breeding programme it is essential to study the inheritance of resistance to brown planthopper in rice mutants MG-8 and MG-18 was studied in the Center For Application of Isotope and Radiation. Pasar Jumat. The result showed that the resistance of MG-8 and MG-18 to brown plathopper was controlled by a single recessive gene and this gene is not allelic to bph-2 of the ASD-7 genotype.


1992 ◽  
Vol 72 (4) ◽  
pp. 1259-1262 ◽  
Author(s):  
B. P. Goplen

A genetic analysis involving P, F1, F2 and F3 in sweetclover (Melilotus alba L.) revealed that the white sepal trait was controlled by a single recessive gene, designated ws. This trait is characterized by chlorophyll-deficient white sepals and several associated pleiotropic effects including: lighter green colour of stems and foliage and a general greenish-red colour of the entire plant, lax and wilted appearance of the white sepal racemes, reduced opening of the mature flower, and a much reduced fertility as measured by percent pod set. Because of these regressive effects associated with the white sepal trait, it has limited use as a plant marker.Key words: Melilotus alba, white sepal, chimera, pleiotropy


1996 ◽  
Vol 121 (1) ◽  
pp. 13-17 ◽  
Author(s):  
R. Bruce Carle ◽  
J. Brent Loy

The expression and inheritance of the fused vein trait in Cucurbita pepo were investigated. The fused vein inbred, NH2405, was crossed to normal lines, NH614, and NHBP10. Reciprocal F1, F2, F3 and BC populations were generated and examined for leaf type segregation in field and greenhouse environments. Although the fused vein phenotype is stable in NH2405, it exhibited a continuum of expression in segregating populations. The onset of vein fusion ranged from the fourth to the tenth leaf stage and degree of fusion varied from slight (1-5 cm) to extreme (10-20 cm). Inheritance ratios varied with population, conditions of production, and direction of cross. Most segregating populations fit either a single or double recessive gene model, however, a quarter of the populations showed no or low fused vein recovery. A feasible explanation for the distorted inheritance is that the fused vein trait is a gametophytic subvital, governed by a single recessive gene, fv. Although less likely, a double recessive, subvital model cannot be ruled out.


1970 ◽  
Vol 12 (3) ◽  
pp. 560-569 ◽  
Author(s):  
R. C. Mehra ◽  
K. S. Rai

Certain plants of Collinsia tinctoria showing chromosomal stickiness at metaphase I and other stages of microsporogenesis were isolated among second generation progeny of an irradiated plant. Genetic analysis of the F1 and F2 progenies from crosses involving such plants showed that this meiotic abnormality can be attributed to a single recessive gene. Besides excessive clumping of chromosomes, this mutant also caused other meiotic abnormalities. These were: increased heteropycnosis at pachytene, high chromosomal fragmentation at prophase I, distortion of normal location and orientation of chromosomes at metaphase I, arrested chromosomal movement and abnormal cytokinesis. All these abnormalities resulted in a high degree of male sterility. Possible mechanisms causing the stickiness of chromosomes during meiosis and consequent abnormalities are discussed.


1972 ◽  
Vol 14 (3) ◽  
pp. 637-644 ◽  
Author(s):  
R. C. Mehra ◽  
K. S. Rai

Certain plants of Collinsia tinctoria showing meiotic abnormalities were isolated from the segregating progenies of irradiated plants (Rai, 1967). In one of these plants, failure of chromosomal pairing was observed, which resulted in a varying number of univalents at metaphase I. Genetic analysis showed that this abnormality is controlled by a single recessive gene. This mutant has been found to be allelic with another meiotic mutant (chromosomal stickiness), reported elsewhere. The mutant showed considerable variation in the nature and extent of abnormal synapsis of the chromosomes. An abnormal chromosomal pairing, chromosomal breakage and sister chromatid reunion, bridges, laggards, neocentromeric activity and differential condensation of the chromosomes were also observed.


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