摘要:

AbstractStudies were undertaken to induce early flowering mutants by ethyl methanesulphonate (EMS) treatments ofBrassica napusseeds. EMS treatments for 12 h of a highly inbredB. napusline TBS had adverse effects on M1plant development and fertility only when concentrations were greater than 1%. However, an EMS concentration of 1.5% did not reduce M1plant fertility to an extent which significantly reduced production of M2seeds.Genetic changes induced by EMS treatment and affecting flowering time were of three main types: (1) Changes within a polygenic system reflected by increased variation in flowering time among M2families. As the increase in variation was due primarily to a higher frequency of later flowering plants, these polygenic changes would be of little value in developing better‐adapted cultivars. (2) Induction of a recessive mutation at a major gene locus which caused M3plants homozygous for the mutant gene to flower at least 20 days earlier than the parental line TB8. (3) Induction of a dominant mutation at a major gene locus which affects flowering time by causing a substantial reduction in vernalization requirement. M2plants carrying the mutant gene flowered as early as 59 days before the parental line.These major gene mutations could be rapidly exploited in the development of agronomically superior cultivars for short‐season, lower rainfall environments in Western Austra

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00118.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractBlack shank, a fuagal disease caused byPhytophthora parasitica var. nicotianae, is a major hazard in the production of burley tobacco (Nicotiutta tubacum L.). Moderate levels of resistance have been bred into cultivars, but little success has been achieved in utilizing high levels of resistance found in the cigar line. Beinhart 1000‐1. Beinhirt 1000‐1 and seven burley cultivars were combined into a synthetic population and three cycles of selection for increased black slunk resistance were conducted. The objectives of this study were (i) t0 estimate genetic variability for agronomic traits in the original base population (Co) and die three selection cycles and (ii) to characterize the effects of selection for black shank resistance on the agronomic traits. Fifty selfed lines From the base population and each of three selection cycles were evaluated in replicated field trials at Lexington and Princeton, KY. Differences among cycle means for six agronomic traits were not statistically significant. Genetic variation for the six traits among lines within cycles was highly significant and did not change during selection. The results indicated that previously assumed associations between black shank resistance in Beinhart 1000‐1 and undesirable agronomic traits were due to chromosomal linkages which were apparently broken by intercrossing. The C3population would be a useful base population for selection to improve agronomic performance in black shank resistant geno

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00119.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAmino acid contents were measured in 109 genotypes from 22 populations of wild emmer wheat,Triticum dicoccoides, across its ecological range in Israel. Plants were grown outdoors on mesic Mr. Carmel, in a standardized environment, without irrigation and fertilization.T. dicoccoideswas high in lysine and isoleucine contents as compared to six other species of wild wheats, but low in threonine and proline. Significant correlations were found among lysine and the other essential amino acids. Significant differences between Israeli populations ofT. dicoccoideswere found for isoleucine, methionine, leucine and threonine, but not for lysine, arginine, proline and glutamic acid. Significant differences between regions were only found in methionine. Ecological factors and allozyme markers appear to be good guidelines for predicting the ecogeographical location and allozymic constitution of specific elite amino acid genotypes, either singly or in combination.T. dicoccoidesmay be used in the future as a promising genetic resource for genetically improving the nutritional value of cultivated wheats.

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00120.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractFrom the total soluble protein ofPseudocercosporella herpotrichoides(Fron) Deighton, specific proteins were isolated and used as antigens. One antiserum proved to be highly sensitive and was used for quantitative determination of eyespot severity in 16 wheat cultivars. The detection limit in ELISA was calculated as 2.2 μg total fungus protein per ml plant sap. From anthesis, genotypes showed the most characteristic and reliable differentiation for a longer period of time, viz. at growth stages 60 and 75. These quantitative differences could be more successfully demonstrated with ELISA than with eye‐spot scoring. There was, however, a close correlation between both traits. The most resistant genotypes carried the genePch‐1with the resistance originating from ‘Capelle Desprez’. Some genotypes originating from this cultivar showed rather low levels of susceptibility, which might be explained by additional effects of the genotypic ba

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00121.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractOne hundred and twenty‐seven spring barley varieties grown in Denmark since 1979 were characterized for resistance genes using 30 powdery mildew isolates. The resistance genes are traced in the pedigrees to verify the results. Eleven named genes, 12 tentatively named genes/resistances and six unknown resistances were found. Resistance in many varieties was based on combinations of either known genes or of known and new factors. The following five new or relatively new resistance genes more or less effective against the present powdery mildew populations were detected: the ‘Mlo’ resistance conferred by the recessivemlogene with the characteristic infection type 0/(4), ‘Ricardo’ and ‘Turkish’ sources having geneMla3in common and ‘Turkish’ withMl(Tu2)in addition. In three varieties the new resistanceMl(IM9)was found in combination with different Mia alleles. Variety ‘Jarek’ has two new uni

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00122.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAmong 16 dwarfing genes identified in wheat (Triticum aestiuvmL. em Thell.), four are known to be associated with insensitivity to the externally‐supplied growth hormone gibberellin (GA).Rht1andRht2(Reduced height 1 and 2, respectively) have been the most extensively used, because of their positive effect on yield. To increase the germplasm pool for dwarfism, a spring rye (Secale cereale) population (UC‐90, CI‐174) was selected because it contains high variability and any useful genes would benefit triticale and wheat as well. Seedlings of the CI‐174 rye population were treated with 50 ppm of GA to identify any insensitive types. GA‐insensitive and ‐sensitive seedlings were identified and, after three generations of selfing, GA‐insensitive and ‐sensitive lines were fixed. Rye insensitive was crossed to a sensitive wheat and to rye and, reciprocally, insensitive wheat was crossed to sensitive rye. The results indicated that a GA‐insensitivity dwarfism system similar to that originally found in wheat also operates in rye and appears to be under simple inheritance. Rye GA‐insensitivity was expressed in triticale. Therefore, it is possible to transfer this new source of insensitivity and dwarfism into

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00123.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstrctShoot and root growth and plant dry weight were determined for twenty four accessions of pearl millet,Pennisetum americanum(L.) Leeke, after two weeks growth in saline solution culture at EC 20 dS m‐1. The EC was achieved using NaCl + CaCl21:1 by weight in solution culture. Although salinity markedly inhibited growth of all accessions, three, 93613, KAT/PM‐2 Kitui, and Kitui local produced significantly greater dry matter, and they and 93612 had longer shoots than the other accessions. Accessions WCA 78 and Bulk 7704 were highly sensitive to salinity in all 3 characters measured. There was considerable variation between the 24 accessions, suggesting that selection for increased tolerance to salinity in pearl millet should be possible. This was examined using normal seed of the cultivar Al/3. A first cycle of selection screened 16,000 seeds after 15 days growth in nutrient solution at EC 26 dS m‐1. 106 individuals were selected to form the S1selection line. Selected seedlings were grown to maturity and polycrossed.In a second cycle of selection, 30,000 S1polycross progeny were screened as previously, but at EC 30 dS m‐1. A selection intensity of 0.08% was achieved. The selected plants were again grown to maturity and again polycrossed.Efficiency of the selection procedure was assessed from comparison in sand culture of the performance of the selected line with the unselected Al/3 line and Kitui local which from the previous assessment of the 24 accessions was rated as relatively salinity tolerant. The selection line was superior to the other two lines at four salinity levels. The results of this study suggest that further improvement in salinity tolerance in pearl millet may be expected from further selection and breeding, using the methods describ

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00124.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractFew studies have examined the effects of selection for high oil or protein content on the chemical composition of cereal seeds. This study was conducted to examine agronomic and bioenergetic consequences that result with changes in the chemical composition of groats of oat (Avena sativaL.). Oat lines with low and high groat‐oil content (GO) and with low and high groat‐protein content (GP) were chosen from each of five cycles of a recurrent selection program for increasing GO and from each of four cycles of a recurrent selection program for increasing protein yield via elevating GP, respectively. These lines were evaluated at three Iowa locations in 1988. The results indicated that GP was not significantly affected by selection for high GO and that GO significantly increased during selection for high protein yield via elevating GP. Both selection procedures resulted in oat lines with higher groat‐energy contents. A bioenergetic cost analysis showed that for GO in the oil population and GP in the protein population to be increased, additional photosynthate needed to be avai

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00125.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe effect of recurrent selection procedure for improving grain yield in autogamous cereals was evaluated in a six‐rowed winter barley population. Gain from selection was estimated by field testing 90 random S2 lines from each of the C0, C1and C2populations. Response to selection for grain yield was 0.78 t/ha from C0to C1and 1.09 t/ha from C1to C2. Broad‐sense heritability and genotypic variance for grain yield remained high in all cycles which suggests further gain from additional selection cycles. Yield increase was due to a higher number of seeds/m2. Significant differences among mean values were observed for heading date (189 days in C0and 182 days in C2), whereas no variation was seen for plant height and 1000‐kernel weight. The proposed recurrent selection procedure appears effective to improve the population and to extract superior genotypes for varietal develo

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00126.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA mutant of oilseed rape (B. napusL.) with waxless leaves was discovered in 1988. Three pairs of reciprocal crosses were made between the mutant (Wl) and 3 normal wax layered lines (Nwl). By the summer planting in Kunming and Wenjiang and the autumn planting in Wenjiang, it was confirmed that theWlcharacter is completely dominant to the normal oppositeNwl. Chi‐square tests revealed that the segregation ratios ofWl to Nwlamong B1and F2plants fit to 1:1 and 3:1, respectively, i.e. the assumption of one gene pair. The yield of 12 hybrids, which were derived fomWland someNwllines, exceeded the check control ‘Zhong You 821’, a best cultivar in Chinese production by 19.31 % on the average. When the seedling had 3–4 leaves, both phenotypes can be accurately determined visually on the field. This material possesses potential value for studies of the genetics and breeding, as a prominent genetic marker inB

ISSN:0179-9541    

DOI:10.1111/j.1439-0523.1992.tb00127.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY