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1.
Influence of rare alleles of β‐carotene hydroxylase and lycopene epsilon cyclase genes on accumulation of provitamin A carotenoids in maize kernels 
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下载免费PDF全文 Rajkumar U. Zunjare Firoz Hossain Vignesh Muthusamy Aanchal Baveja Hema S. Chauhan Nepolean Thirunavukkarasu Supradip Saha Hari S. Gupta 《Plant Breeding》2017,136(6):872-880
Vitamin A deficiency is one of the major health problems worldwide. Traditional yellow maize possesses very low provitamin A (proA) concentration in endosperm. The influence of rare alleles of β‐carotene hydroxylase (crtRB1) and lycopene epsilon cyclase (lcyE) genes capable of enhancing proA concentration was studied in four BC2F2 populations generated using subtropical inbreds and CIMMYT‐HarvestPlus lines. The occurrence of severe segregation distortion for crtRB1 gene was observed, while lcyE gene was segregated as per Mendelian ratio. Genotype with favourable allele of crtRB1 (CC) had a significant effect on β‐carotene (BC) (7.9‐fold), β‐cryptoxanthin (BCX) (twofold) and proA (5.5‐fold) accumulation, compared to unfavourable genotype (C+C+). Genotype with favourable allele of lcyE (LL) showed 2.1‐fold, 1.6‐fold and twofold significant enhancement in BC, BCX and proA, respectively, over unfavourable genotype (L+L+) in pooled analysis. Of the nine genotypes, double homozygote (CC/LL) had the highest mean BC (12.60 μg/g), BCX (4.44 μg/g) and proA (14.82 μg/g), and combined effect was significantly better than individual gene effects or any other combinations. The information generated here would be useful in designing strategy for proA enrichment in subtropical maize. 相似文献
2.
Maize (Zea mays L.) is an important staple food crop in West and Central Africa (WCA). However, its production is constrained by drought. Knowledge and understanding of the genetics of hybrid performance under drought is invaluable in designing breeding strategies for improving maize yield. One hundred and fifty hybrids obtained by crossing 30 inbreds in sets using the North Carolina Design II plus six checks were evaluated under drought and well‐watered conditions for 2 years at three locations in Nigeria. The objectives of the studies were to (i) determine the mode of gene action controlling grain yield and other important agronomic traits of selected early inbred lines, (ii) examine the relationship between per se performance of inbreds and their hybrids and (iii) identify appropriate testers for maize breeding programmes in WCA. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant (P < 0.01) for grain yield and other traits under the research environments. The GCA accounted for 64.5 % and 62.3 % of the total variation for grain yield under drought and well‐watered conditions, indicating that additive gene action largely controlled the inheritance of grain yield of the hybrids. Narrow‐sense heritability was 67 % for grain yield under drought and 49 % under well‐watered conditions. The correlations between traits of early‐maturing parental lines and their hybrids were significant (P < 0.01) under drought, well‐watered and across environments. Mid‐parent and better‐parent heterosis for grain yield were 45.3 % and 18.4 % under drought stress and 111.9 % and 102.6 % under well‐watered conditions. Inbreds TZEI 31, TZEI 17, TZEI 129 and TZEI 157 were identified as the best testers. Drought‐tolerant hybrids with superior performance under stress and non‐stress conditions could be obtained through the accumulation of favourable alleles for drought tolerance in both parental lines. 相似文献
3.
Drought and low soil fertility are considered the most important abiotic stresses limiting maize production in sub-Saharan
Africa. Knowledge of the combining ability and diversity of inbred lines with tolerance to the two stresses and for those
used as testers would be beneficial in setting breeding strategies for stress and nonstress environments. We used 15 tropical
maize inbred lines to (i) evaluate the combining ability for grain yield (GY), (ii) assess the genetic diversity of this set
of inbred lines using RFLP, SSR, and AFLP markers, (iii) estimate heterosis and assess the relationship between F1 hybrid performance, genetic diversity and heterosis, and (iv) assess genotype × environment interaction of inbred lines and
their hybrids. The F1 diallel hybrids and parental inbreds were evaluated under drought stress, low N stress, and well-watered conditions at six
locations in three countries. General combining ability (GCA) effects were highly significant (P < 0.01) for GY across stresses and well-watered environments. Inbred lines CML258, CML339, CML341, and CML343 had the best
GCA effects for GY across environments. Additive genetic effects were more important for GY under drought stress and well-watered
conditions but not under low N stress, suggesting different gene action in control of GY. Clustering based on genetic distance
(GD) calculated using combined marker data grouped lines according to pedigree. Positive correlation was found between midparent
heterosis (MPH) and specific combining ability (SCA), GD and GY. Hybrid breeding program targeting stress environments would
benefit from the accumulation of favorable alleles for drought tolerance in both parental lines. 相似文献
4.
Summary The variation of response to acetochlor was studied in a two-year experiment carried out by subjecting 18 maize (Zea mays L.) inbred lines to three herbicide rates (0, 2.5 and 5 l a.i./ha). In both years some inbred lines consistently exhibited an evident susceptibility, with symptoms consisting of the seedling curling up below the soil surface and causing impaired field emergence. The results were poor plant density and lower grain yield in comparison to control. In contrast, other lines showed a satisfactory level of tolerance.Then, to gather data on the inheritance of response to acetochlor, four tolerant inbreds (T) and four susceptible inbreds (S) were crossed to obtain four T×T, four S×S, four S×T and the corresponding four T×S two-way hybrids. These hybrids were studied together with parental lines by applying the same herbicide rates used in the previous trial. The S×S hybrids showed susceptibility to the herbicide and the T×T were tolerant, whereas the S×T and the T× S hybrids showed a tolerance very close to that of the T×T hybrids. No difference was found between S×T and the corresponding T×S hybrids as to herbicide response. On average, the 16 hybrids exhibited greater tolerance than the eight parental lines, with each hybrid group being more tolerant than its parental line group. These results indicate that tolerance to acetochlor is prevailingly dominant, that action of extranuclear genes should be ruled out, and that the level of plant vigour can affect herbicide reactiveness. 相似文献
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6.
A set of 23 Quality Protein Maize (QPM) lines, including 13 lines developed in India and 10 lines at CIMMYT (International
Maize and Wheat Improvement Center), Mexico, was analyzed using microsatellite or simple sequence repeat (SSR) markers. Polymorphic
profiles for 36 SSR loci have aided in differentiating the QPM inbred lines. The study resulted in identification of SSR markers,
such as bnlg439, phi037, bnlg125, dupssr34 andbnlg105, with high polymorphism information content in the selected QPM genotypes. Detection of 30 unique/rare SSR alleles could
contribute to effective differentiation of 14 of the 23 QPM inbreds. An opaque2-specific microsatellite marker, phi057, also facilitated differentiation of opaque2-carrying QPM
inbreds from the non-opaque genotypes. Analysis using SSR markers indicated high levels of heterozygosity in majority of the
Indian QPM lines and in one CIMMYT QPM inbred, CML188. Cluster analysis using SSR data, followed by canonical discriminant
analysis, clearly distinguished the Indian QPM inbreds from those developed at CIMMYT. The cluster patterns were largely in
congruence with the available pedigree information of the QPM inbreds studied. The study demonstrates the effectiveness of
SSR markers in QPM genotype discrimination and analysis of genetic relationships, and could potentially contribute towards
effective utilization of the elite QPM germplasm in Indian maize breeding programmes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Yongshen Wu Wenguo Liu Xinhai Li Mingshun Li Degui Zhang Zhuanfang Hao Jianfeng Weng Yunbi Xu Li Bai Shihuang Zhang Chuanxiao Xie 《Euphytica》2011,180(2):281-290
Limited information is available on genetic variation in low-nitrogen (low-N) stress tolerance and N-use efficiency (NUE) among maize inbreds. To unveil this information, a panel of 189 diverse maize inbred lines was evaluated under contrasting levels of N availability over 2 years. Low-N agronomic efficiency (LNAE), absolute grain yield (GY) at low-N conditions, and the ratio between GY at low-N and optimum-N conditions were taken into account to represent low-N tolerance. Additionally, N-agronomic efficiency (NAE) along with other agronomic traits was also analyzed. Analysis of variance revealed significant effects of genotype on LNAE, NAE, and GY. The estimated broad-sense heritability was 0.38 for LNAE while it was only 0.11 for NAE, implying that selection based on LNAE should be more effective than NAE. LNAE exhibited highly positive genotypic and phenotypic correlations with GY, ear kernel number (EKN), kernel weight, plant height (PH), and chlorophyll content at low-N conditions, while it was negatively correlated with grain-N content and anthesis-silking interval. Path analysis indicated that the EKN at low-N stress had the highest positive effects on LNAE. 相似文献
8.
Low soil nitrogen (Low N), Striga hermonthica and recurrent drought are major constraints to maize production and productivity in sub-Saharan Africa (SSA). Only a few extra-early maturing hybrids with combined tolerance to drought, Striga and low N have been commercialized in SSA. The objectives of the study were to determine the general combining ability (GCA) and specific combining ability (SCA) effects of grain yield and other traits, classify the inbreds into heterotic groups using the SCA effects of grain yield, and the heterotic group’s SCA and GCA of grain yield (HSGCA) methods, and examine the performance of hybrids under contrasting environments. Sixty-three extra-early white maize inbred lines containing genes from Zea diploperennis were crossed to four elite testers to obtain 252 single-cross hybrids and evaluated together with four checks at four locations for 2 years under drought, Striga-infested, low N and optimal environments in Nigeria. The GCA and SCA effects were significant (P ≤ 0.01) with preponderance of GCA over SCA effects for all measured traits indicating that additive genetic effects were predominant in the lines under all the contrasting environments. The HSGCA was more efficient than the SCA method in the classification of the inbreds into heterotic groups. The hybrids TZdEEI 74 × TZEEI 13 and TZdEEI 74 × TZEEI 29 were high yielding and most stable across research environments. These hybrids should be further evaluated in on-farm trials to confirm the consistency of performance for commercialization in SSA. 相似文献
9.
Inheritance of zein components in maize has been studied by a highresolution system of acidic continuous polyacrylamide gel electrophoresis. This method revealed extraordinarily high polymorphism of zeins. Previously, three multigenic loci, Zep1, Zep2 and Zep3, encoding most zein polypeptides were identified. Four other loci control the synthesis of some minor components. Single F2 grains from 16 hybrid combinations involving 19 inbred lines were analysed. Correspondingly, 12 and 14 alleles of the Zep1 and the Zep2 loci were identified for 19 inbreds. Six alleles of the Zep3 locus were identified in five crosses. All 32 alleles of three multigenic loci were included in the catalogue of zein alleles. Genetic nomenclature for the alleles designation is proposed. Such nomenclature is in good agreement with ‘a standard for maize genetics nomenclature. The catalogue may serve for practical use and as basis for more detailed genetic studies of zeins. Practical application of the catalogue in maize breeding is discussed. 相似文献
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11.
Downy mildews cause considerable damage to maize (Zea mays L.) worldwide, particularly in the tropical Asia. We have evaluated a set of 42 tropical/sub-tropical maize inbred lines
developed in different countries in Asia (India, Thailand and Philippines), and Mexico, for analysing the genetic variability
for resistance to sorghum downy mildew [Peronosclerospora sorghi; SDM] and Rajasthan downy mildew [P. heteropogoni; RDM]. Experiments were carried out in replicated trials under artificial infection in field conditions against SDM and RDM
at Mandya in Karnataka, India, and Udaipur in Rajasthan, India, respectively, during 1999 and 2000. The study resulted in
identification of five inbred lines offering consistent and strong resistance to both SDM and RDM, while several inbred lines
revealed resistance only to RDM. It was also revealed that the SDM-resistant inbreds are invariably resistant to RDM, while
the RDM-resistant inbreds might show differential responses to the SDM. The maize inbred lines identified in this study with
broad-spectrum resistance to downy mildews could be potentially useful for basic and applied research work on downy mildews
in tropical Asia.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Rajat Goswami Rajkumar Uttamrao Zunjare Suphiya Khan Aanchal Baveja Vignesh Muthusamy Firoz Hossain 《Plant Breeding》2019,138(2):174-183
Vitamin A deficiency in humans is a widespread health problem. Quality protein maize (QPM) is a popular food rich in lysine and tryptophan, but poor in provitamin A (proA). Here, we report the improvement of an elite QPM inbred, HKI1128Q for proA using marker‐assisted introgression of crtRB1‐favourable allele. HKI1128 was one of the parental lines of three popular hybrids in India and was converted to QPM in our earlier programme. Severe segregation distortion for crtRB1 was observed in BC1F1, BC2F1 and BC2F2. Background selection by 100 SSRs revealed mean recovery of 91.07% recurrent parent genome varying from 88.78% to 93.88%. Across years, introgressed progenies possessed higher mean β‐carotene (BC: 9.22 µg/g), β‐cryptoxanthin (BCX: 3.05 µg/g) and provitamin A (proA: 10.75 µg/g) compared to HKI1128Q (BC: 2.26 µg/g, BCX: 2.26 µg/g and proA: 3.38 µg/g). High concentration of essential amino acids, viz. lysine (mean: 0.303%) and tryptophan (0.080%) in endosperm, was also retained. Multi‐year evaluation showed that introgressed progenies possessed similar grain yield (1,759–1,879 kg/ha) with HKI1128Q (1,778 kg/ha). Introgressed progenies with higher lysine, tryptophan and proA hold immense potential as donors and parents in developing biofortified hybrids. 相似文献
13.
Assessing the genetic diversity of Portuguese maize germplasm using microsatellite markers 总被引：4，自引：0，他引：4
A collection of Portuguese maize accessions representing a valuable source of genes for introduction into modern cultivars
is stored at the Portuguese Plant Germplasm Bank (Banco Português de Germoplasma Vegetal—BPGV). To assess genetic diversity
among inbreds, microsatellite analysis was carried out for 54 inbred lines representing the diversity of Portuguese dent and
flint maize germplasm. Fifty American and other European elite inbreds were also analysed for comparison. Fifteen microsatellite
loci distributed throughout the maize genome were chosen based on their repeat unit and base composition. A total of 80 alleles
were detected with an average allele number of 5.33 per locus. Polymorphism information content (PIC) values and observed
genetic distances showed the existence of large variability among inbreds. Cluster analysis indicated that almost all of the
inbreds could be distinguished from each other and Portuguese inbreds were present in all clusters formed. These associations
were consistent with the known pedigree records of the inbreds, confirming a mixed origin of Portuguese materials. Comparative
analysis of microsatellite diversity among groups was established according to important traits for both breeding and line
identification. This revealed that, although most of the genetic diversity (>95%) was attributable to differences among inbreds
of different groups, the existence of phenotypic differentiation in endosperm colour, kernel type and cob colour could be
suggested for grouping. These findings support the joint use of molecular and morphological traits in management of the germplasm
collection. In this study, SSR markers proved to be effective to characterise and identify maize inbred lines, and demonstrate
associations among them.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Maize hybrids that are tolerant to drought at the seedling stage are needed to boost productivity in the rainforest agro-ecology of West Africa. Genetics of tolerance of maize seedling to drought stress is not well understood and is poorly documented. The objectives of this study were to screen early-maturing maize lines for seedling drought tolerance, determine the inheritance and the combining ability of selected inbred lines, and evaluate the performance of seedling drought-tolerant hybrids under field conditions. Forty-nine early maize lines were screened for drought tolerance at the seedling stage. Ten drought-tolerant and two susceptible inbred lines were selected and used in diallel crosses to generate 66 hybrids. The twelve inbred lines and their hybrids were evaluated under induced drought at seedling stage in the screen house and under marginal growing conditions on the field for two seasons. Data collected were subjected to analysis of variance using the DIALLEL-SAS program. Mean squares for both GCA and SCA were significant for most traits in all research environments, indicating that additive and non-additive gene actions are controlling seedling traits under stress conditions. However, for most traits, SCA was preponderant over GCA in all environments, indicating overdominating effect of non-additive gene action. Which in turn implied that the best improvement method for the traits is hybridization. Inbred TZEI 7 had the best GCA effect for seedling traits under screenhouse conditions and for grain yield and other agronomic traits under drought conditions in the field. Hybrids TZEI 357?×?TZEI 411 and TZEI 380?×?TZEI 410 showed superior SCA effects under screen house conditions. In conclusion, the study established wide genetic variability for drought tolerance at seedling stage among tropical early-maturing maize germplasm however, the non-additive gene action was more important for most seedling traits. 相似文献
15.
Summary S1 to S5 inbred lines, derived from a maize population bred for its overall resistance to three tropical viruses, were screened for resistance to maize streak virus (MSV) by artificial plant infection using viruliferous leafhoppers. Symptoms were rated and intra-line frequency distributions studied for all pedigree inbred lines. Mortality due to MSV was very low among these inbreds. Symptoms appeared later, developed slower and were less severe than in the susceptible control hybrid. Results of a study of 500 S1 and 93 S2 lines suggested that resistance is under genetic control via a system involving loci with major genes (with dominance for resistance) controlling high to complete resistance, associated with a genetic system involving loci with minor genes controlling partial resistance. Lines expressing complete resistance to MSV were developed from 5 cycles of inbreeding and selection. The relevance of such complete and partial resistance is discussed.Abbreviations MRPS
Mean Rating for Plants exhibiting Symptoms 相似文献
16.
Summary The genetic control of endosperm modification in 12 opaque-2 maize (Zea mays L.) inbred lines was investigated by means of a diallel cross experiment conducted across two environments. Kernel vitreousness and kernel hardness were determined by partially dominant genes. Additive gene action was largely responsible for kernel modification. A favourable general combining ability for kernel vitreousness and kernel hardness was positively correlated with an accumulation of dominant kernel modifying genes. South African sources of endosperm modifiers have been found to be similar to those used in other quality protein maize breeding programmes. Certain inbred lines displayed sufficient genetic potential for use in a quality protein maize hybrid breeding programme. 相似文献
17.
Identification of hybrids for commercialization is crucial for sustainable maize production in sub-Saharan Africa (SSA). One hundred and ninety test crosses, 10 tester × tester crosses + 10 hybrid checks were evaluated across 11 environments, 2017 to 2019. Inheritance of grain yield under Striga infestation, optimal and across environments was influenced by additive genetic action, but there was greater influence of nonadditive gene action under drought stress conditions. Nine, seven and two inbreds had significant and positive general combining ability (GCA) effects for grain yield under Striga-infested, optimal and drought stress environments, respectively, and would contribute high grain yield to their progenies. Heterotic grouping methods based on specific and GCA, GCA effects of multiple traits and DArTseq markers classified the inbreds into five, three and two heterotic groups, respectively, across research conditions. The DArTseq markers method that classified the inbred lines into two major heterotic groups and was one of the most efficient methods should be adopted for practical purposes in maize breeding programmes in SSA. Hybrids TZEI 7 × TZdEI 352, TZEI 1238 × TZEI 7 and TZEI 1252 × TZEI 7 had outstanding grain yield under contrasting environments and should be tested on-farm for commercialization in SSA. 相似文献
18.
玉米自交系苗期耐冷性鉴定 总被引：8，自引：0，他引：8
采用低温下发芽鉴定,田间分期播种和人工低温处理完整植株等方法,研究了8个玉米自交系苗期耐冷性反应.结果表明:玉米自交系的耐冷性可以分为强、中、弱等类型.玉米自交系的主要耐冷特征有耐冷性总指数、发芽临界温度、早播幼苗地上部分干重、早播叶片束缚水含量、叶片膜透性相对电导值达50%的时间、叶片超弱发光强度达1/2Max的时间和植株干枯率达50%的时间等指标.常温下游离脯氨酸含量与耐冷性呈正相关,低温下脯氨酸积累量与耐冷性呈负相关. 相似文献
19.
Benjamin Annor Baffour Badu-Apraku Daniel Nyadanu Richard Akromah Morakinyo A. B. Fakorede 《Plant Breeding》2020,139(4):708-716
Identification of heterotic groups and efficient testers, which are important prerequisites for the development of outstanding hybrids, has been a major challenge to its success, especially for early and extra-early germplasm. This study was carried out to (a) identify the most efficient heterotic grouping method for classifying a set of inbred lines and (b) determine the efficiency of testers in classifying inbred lines into heterotic groups. A total of 205 hybrids obtained by crossing 41 inbred lines with five standard testers were evaluated together with five hybrid checks under drought, low soil nitrogen (N), Striga-infested and optimal environments in Nigeria between 2014 and 2016. The heterotic group's specific and general combining ability (HSGCA) method was more effective in classifying the inbred lines into heterotic groups. Testers TZEI 17 and TZEI 23 were the most efficient across environments and could be invaluable for classifying other lines into heterotic groups and assessing combining ability of maize inbreds. In addition, these testers and heterotic groups represent an invaluable resource for development of outstanding hybrids in sub-Saharan Africa (SSA). 相似文献
20.
Cluster analysis of RFLP data from related maize inbred lines of the BSSS and LSC heterotic groups and comparison with pedigree data 总被引：2，自引：0，他引：2
Summary In this study, 31 elite inbred lines of maize (Zea mays L.) were analyzed with 149 clone-enzyme combinations for their respective RFLP profiles. Objectives were (1) to determine the utility of RFLPs for estimation of genetic similarties among 16 inbred lines from the Iowa Stiff Stalk Synthetic (BSSS) and among 15 inbred lines from the Lancaster Sure Crop (LSC) heterotic groups and (2) to compare genetic similarities based on molecular markers with those based on pedigree information. Coefficients of genetic similarity (GS) and coancestry (f) between pairs of lines from the same heterotic group were calculated from RFLP and pedigree data, respectively. For lines from the BSSS heterotic group, cluster analyses based on RFLP and pedigree data revealed similar associations. GS and f values were closely correlated (r=0.70) for related BSSS lines. For lines from the LSC heterotic group, considerable discrepancies existed between the GS and f values, especially for those pairs involving inbreds Va22 and Lo924. Effect of selection and/or erroneous pedigree records are discussed as possible explanations for the low correlation of GS and f values (r=0.07) for related LSC lines. RFLPs seem useful for investigation of relationships among maize inbreds, verification of pedigree records, and quantification of the degree of relatedness. 相似文献