Assessing Effect of Marker-Based Improvement of Maize Synthetics on Agronomic Performance, Carotenoid Content, Combining Ability and Heterosis

Vitamin A deficiency (VAD) is a serious problem in sub-Saharan Africa (SSA) and other parts of the world. Understanding the effect of marker-based improvement (MARS) of two maize synthetics (HGA and HGB) representing different heterotic groups on their agronomic performance, carotenoid content, and combining abilities could help identify suitable sources to develop divergent inbred lines for optimizing heterosis. This study involved three selection cycles each of the two synthetics and their nine varietal-cross hybrids together with a released check variety was conducted across four diverse locations in Nigeria in 2018 and 2019. Environment and hybrid effects were significant on grain yield and other agronomic traits as well as provitamin A content and other carotenoids. Genetic improvement per cycle of MARS in the parental synthetics was 15% for provitamin A, 25% for β-carotene and 26% for lutein in HGA and 4% for grain yield, 3% for zeaxanthin and 5% for α-carotene in HGB. Grain yield and agronomic traits of the two maize synthetics were controlled by additive and non-additive gene effects, while provitamin A content and other carotenoids were mainly controlled by additive gene effects. Some selection cycles which were high in grain yield and provitamin A content were identified as potential sources of new and divergent maize inbred lines in maize breeding programs. Some varietal-cross hybrids expressed significant mid-parent heterosis for grain yield and moderate mid-parent heterosis for provitamin A, β-carotene and xanthophylls. These hybrids could be commercialized at reasonable prices to small-scale farmers in rural areas that are most affected by vitamin A deficiency.

Download Full-text

Combining Ability and Heterosis for Endosperm Carotenoids and Agronomic Traits in Tropical Maize Lines

Frontiers in Plant Science ◽

10.3389/fpls.2021.674089 ◽

2021 ◽

Vol 12 ◽

Author(s):

Girum Azmach ◽

Melaku Gedil ◽

Charles Spillane ◽

Abebe Menkir

Keyword(s):

Combining Ability ◽

Agronomic Traits ◽

Vitamin A Deficiency ◽

Public Health Problem ◽

Inbred Lines ◽

Provitamin A ◽

F1 Hybrids ◽

Carotenoid Content ◽

Gene Effects ◽

Gxe Interaction

Provitamin A enrichment of staple crops through biofortification breeding is a powerful approach to mitigate the public health problem of vitamin A deficiency in developing countries. Twenty-four genetically diverse yellow and orange endosperm maize inbred lines with differing levels of provitamin A content were used for the analysis of their combining ability. Each inbred line was developed from crosses and backcrosses between temperate and tropical germplasm. The inbred lines were grouped into different sets according to their provitamin A levels and were then intercrossed in a factorial mating scheme to generate 80 different single-cross hybrids. The hybrids were evaluated in field trials across a range of agroecological zones in Nigeria. The effect of hybrids was significant on all the measured provitamin A and non-provitamin A carotenoids and agronomic traits. While the effect of genotype-by-environment (GxE) interaction was significant for almost all traits, it was a non-crossover-type interaction for carotenoid content. Partitioning of the variances associated with the carotenoid and agronomic traits into their respective components revealed the presence of significant positive and negative estimates of general combining ability (GCA) and specific combining ability (SCA) effects for both carotenoid content and agronomic traits. The preponderance of GCA effects indicates the importance of additive gene effects in the inheritance of carotenoid content. We found F1 hybrids displaying high parent heterosis for both provitamin A content and agronomic performance. Our study demonstrates that provitamin A biofortification can be effectively implemented in maize breeding programs without adverse effects on important agronomic traits, including grain yield.

Download Full-text

Cassava with enhanced β-carotene maintains adequate vitamin A status in Mongolian gerbils (Meriones unguiculatus) despite substantial cis-isomer content

British Journal Of Nutrition ◽

10.1017/s0007114508184720 ◽

2009 ◽

Vol 102 (3) ◽

pp. 342-349 ◽

Cited By ~ 25

Author(s):

Julie A. Howe ◽

Bussie Maziya-Dixon ◽

Sherry A. Tanumihardjo

Keyword(s):

Vitamin A ◽

Vitamin A Deficiency ◽

Meriones Unguiculatus ◽

Provitamin A ◽

Carotenoid Content ◽

Mongolian Gerbils ◽

Serum Retinol ◽

Vitamin A Status ◽

Isomer Content ◽

Β Carotene

Efforts to increase β-carotene in cassava have been successful, but the ability of high-β-carotene cassava to prevent vitamin A deficiency has not been determined. Two studies investigated the bioefficacy of provitamin A in cassava and compared the effects of carotenoid content and variety on vitamin A status in vitamin A-depleted Mongolian gerbils (Meriones unguiculatus). Gerbils were fed a vitamin A-free diet 4 weeks prior to treatment. In Expt 1, treatments (ten gerbils per group) included 45 % high-β-carotene cassava, β-carotene and vitamin A supplements (intake matched to high-β-carotene cassava group), and oil control. In Expt 2, gerbils were fed cassava feeds with 1·8 or 4·3 nmol provitamin A/g prepared with two varieties. Gerbils were killed after 4 weeks. For Expt 1, liver vitamin A was higher (P < 0·05) in the vitamin A (1·45 (sd 0·23) μmol/liver), lower in the control (0·43 (sd 0·10) μmol/liver), but did not differ from the β-carotene group (0·77 (sd 0·12) μmol/liver) when compared with the high-β-carotene cassava group (0·69 (sd 0·20) μmol/liver). The bioconversion factor was 3·7 μg β-carotene to 1 μg retinol (2 mol:1 mol), despite 48 % cis-β-carotene [(Z)-β-carotene] composition in cassava. In Expt 2, cassava feed with 4·3 nmol provitamin A/g maintained vitamin A status. No effect of cassava variety was observed. Serum retinol concentrations did not differ. β-Carotene was detected in livers of gerbils receiving cassava and supplements, but the cis-to-trans ratio in liver differed from intake. Biofortified cassava adequately maintained vitamin A status and was as efficacious as β-carotene supplementation in the gerbil model.

Download Full-text

Screening of Provitamin-A Maize Inbred Lines for Drought Tolerance Using β-carotene Content: Morphophysiological and Biochemical Traits

Agronomy ◽

10.3390/agronomy9110692 ◽

2019 ◽

Vol 9 (11) ◽

pp. 692 ◽

Cited By ~ 2

Author(s):

Aleck Kondwakwenda ◽

Julia Sibiya ◽

Rebecca Zengeni ◽

Cousin Musvosvi ◽

Samson Tesfay

Keyword(s):

Drought Tolerance ◽

Vitamin A Deficiency ◽

Inbred Lines ◽

Sub Saharan Africa ◽

Provitamin A ◽

Biochemical Traits ◽

Carotene Content ◽

Maize Productivity ◽

Sub Saharan ◽

Β Carotene

Provitamin A maize (Zea mays L.) biofortification is an ideal complementary means of combating vitamin A deficiency (VAD) in sub-Saharan Africa where maize consumption is high coupled by high VAD incidences. However, drought remains a major abiotic constraint to maize productivity in this region. Comprehensive drought screening of initial breeding materials before advancing them is important to achieve genetic gain. In this study, 46 provitamin-A inbred lines were screened for drought tolerance in the greenhouse and field under drought and optimum conditions using β-carotene content (BCC), grain yield (GY), and selected morphophysiological and biochemical traits. The results revealed that BCC, morphophysiological and biochemical traits were effective in discriminating among genotypes. Number of ears per plant (EPP), stomatal conductance (Gs), delayed leaf senescence (SEN), leaf rolling (RL), chlorophyll content (CC) and free proline content (PC) proved to be ideal traits to use when indirectly selecting for GY by virtue of having relative efficiency of indirect selection values that are greater than unity and considerable genetic variances under either or both conditions. The findings of this study form the basis of initial germplasm selection when improving provitamin A maize for drought tolerance.

Download Full-text

Analysis of Combining Ability in Rice Varieties for Quantitative Traits

Notulae Scientia Biologicae ◽

10.15835/nsb11310449 ◽

2019 ◽

Vol 11 (3) ◽

pp. 436-439

Author(s):

Ghaffar KIANI

Keyword(s):

Grain Yield ◽

Combining Ability ◽

Agronomic Traits ◽

Block Design ◽

Rice Varieties ◽

Gene Effects ◽

Breeding Programs ◽

Grain Length ◽

Additive Gene Effects ◽

Additive Gene

Rice is staple food in Iran. Despite of high quality of local rice, their grain yield is low. In hybridization breeding programs, selection of suitable parents is an essential role for developing new combinations with broadens genetic diversity. Combining ability of local rice varieties namely ‘Hashemi’, ‘Sang Jo’ and ‘Tarom Deylamani’ and ‘Nemat’ was evaluated in a partial diallele analysis for agronomic traits in a randomized complete block design at Sari Agricultural Sciences and Natural Resources University. General combining ability (GCA) and specific combining ability (SCA) variances showed predominated role of additive gene effects in the inheritance of grain length. Both additive and non-additive components of genetic variances were important in the inheritance of traits like grain yield, plant height, panicle length, total grains per panicle, grain length and grain length to width. However, non-additive gene effects were seen for tiller number. Results showed that ‘Nemat’ was the best general combiner for most of characters followed by ‘Tarom Deylamani’. The cross of ‘Hashemi’ × ‘Tarom Deylamani’ was suggested to exploitation of heterosis breeding for increasing yield and its components in rice breeding programs.

Download Full-text

Comparative Assessment of Effectiveness of Alternative Genotyping Assays for Characterizing Carotenoids Accumulation in Tropical Maize Inbred Lines

Agronomy ◽

10.3390/agronomy11102022 ◽

2021 ◽

Vol 11 (10) ◽

pp. 2022

Author(s):

Abdoul-Raouf Sayadi Maazou ◽

Melaku Gedil ◽

Victor O. Adetimirin ◽

Silvestro Meseka ◽

Wende Mengesha ◽

...

Keyword(s):

Vitamin A Deficiency ◽

Inbred Lines ◽

Provitamin A ◽

Carotenoid Content ◽

Functional Markers ◽

Favorable Alleles ◽

Specific Pcr ◽

Maize Inbred Lines ◽

Maize Varieties ◽

Allele Specific

The development of maize varieties with increased concentration of Provitamin A (PVA) is an effective and affordable strategy to combat vitamin A deficiency in developing nations. However, the considerably high cost of carotene analysis poses a major challenge for maize PVA biofortification, prompting the use of marker-assisted selection. Presently, two types of genotyping with PVA trait-linked functional markers have been developed and extensively used in breeding programs. The two systems are low throughput gel-based genotyping and genotyping with Kompetitive Allele-Specific PCR (KASP) single nucleotide polymorphism (SNPs) markers. Although the KASP SNPs genotyping was developed to replace the gel-based genotyping, studies have not been conducted to compare the effectiveness of the KASP SNPs markers with the gel-based markers. This study was conducted to assess the carotenoid content of 64 tropical PVA biofortified maize inbred lines containing temperate germplasm in their genetic backgrounds and screen them with both gel-based and KASP markers of PSY1, LCYE and crtRB1 genes. Many of the 64 inbred lines had PVA concentrations surpassing the 15 µg/g provitamin A breeding target set by the HarvestPlus Challenge Program. Favorable alleles of crtRB1, crtRB1 and the KASP SNPs markers were detected in 25 inbred lines with high PVA concentrations. Inbred lines with the favorable alleles of LCYE had the highest concentrations of non-PVA carotenoids, whereas those with the favorable alleles of crtRB1 had high levels of PVA carotenoids. Data from the sequenced region of LCYE revealed one SNP in the first intron that clearly differentiated the high and low β-carotene maize inbred lines. The results of our study demonstrate that the automated KASP SNPs markers can replace the gel-based genotyping for screening a large number of early generation maize inbred lines for PVA content.

Download Full-text

Combining Ability of Quality Protein Maize Inbred Lines for Yield and Morpho-Agronomic Traits under Optimum as Well as Combined Drought and Heat-Stressed Conditions

Agronomy ◽

10.3390/agronomy10020184 ◽

2020 ◽

Vol 10 (2) ◽

pp. 184 ◽

Cited By ~ 1

Author(s):

Nyasha E. Chiuta ◽

Charles S. Mutengwa

Keyword(s):

Heat Stress ◽

Combining Ability ◽

Agronomic Traits ◽

Inbred Lines ◽

Sub Saharan Africa ◽

Optimum Conditions ◽

Gene Effects ◽

Additive Gene Effects ◽

Additive Gene ◽

Drought And Heat Stress

Drought and heat stress have perceptibly become major maize (Zea mays L.) yield reducing factors in Sub-Saharan Africa. As such, the objectives of this study were to: (i) determine the type of gene action conditioning tolerance to combined drought and heat stress (CDHS), and (ii) identify inbred lines with good combining ability for yield and other morpho-agronomic traits under CDHS. Twenty-four single cross hybrids (SCHs) obtained from crossing 10 inbred lines in a 4 × 6 North Carolina Design II, and a drought-tolerant check, were evaluated under CDHS and optimum conditions in the field. The experiment was laid out in a 5 × 5 alpha lattice incomplete block design, replicated three times. Additive gene effects influenced all the traits under CDHS except grain yield, which was influenced by non-additive gene effects. A preponderance of additive genetic effects was observed for all traits recorded under optimum conditions. Inbred lines L30, L6, L5, L17 and L2 showed good combining ability for yield under CDHS, indicating that they could be good parental lines in hybridization programs. Based on the results, SCHs L2*30, L6*13 and L5*18 exhibited high specific combining ability (SCA) effects for yield under CDHS. These hybrids are recommended for further multi-locational evaluation to determine the stability of their performance.

Download Full-text

Multi-strategy engineering greatly enhances provitamin A carotenoid accumulation and stability in Arabidopsis seeds

aBIOTECH ◽

10.1007/s42994-021-00046-1 ◽

2021 ◽

Author(s):

Tianhu Sun ◽

Qinlong Zhu ◽

Ziqing Wei ◽

Lauren A. Owens ◽

Tara Fish ◽

...

Keyword(s):

Vitamin A Deficiency ◽

Seed Maturation ◽

Provitamin A ◽

Carotenoid Content ◽

Total Carotenoid ◽

Carotenoid Accumulation ◽

Provitamin A Carotenoids ◽

Total Carotenoid Content ◽

And Storage ◽

Β Carotene

AbstractStaple grains with low levels of provitamin A carotenoids contribute to the global prevalence of vitamin A deficiency and therefore are the main targets for provitamin A biofortification. However, carotenoid stability during both seed maturation and postharvest storage is a serious concern for the full benefits of carotenoid biofortified grains. In this study, we utilized Arabidopsis as a model to establish carotenoid biofortification strategies in seeds. We discovered that manipulation of carotenoid biosynthetic activity by seed-specific expression of Phytoene synthase (PSY) increases both provitamin A and total carotenoid levels but the increased carotenoids are prone to degradation during seed maturation and storage, consistent with previous studies of provitamin A biofortified grains. In contrast, stacking with Orange (ORHis), a gene that initiates chromoplast biogenesis, dramatically enhances provitamin A and total carotenoid content and stability. Up to 65- and 10-fold increases of β-carotene and total carotenoids, respectively, with provitamin A carotenoids composing over 63% were observed in the seeds containing ORHis and PSY. Co-expression of Homogentisate geranylgeranyl transferase (HGGT) with ORHis and PSY further increases carotenoid accumulation and stability during seed maturation and storage. Moreover, knocking-out of β-carotene hydroxylase 2 (BCH2) by CRISPR/Cas9 not only potentially facilitates β-carotene accumulation but also minimizes the negative effect of carotenoid over production on seed germination. Our findings provide new insights into various processes on carotenoid accumulation and stability in seeds and establish a multiplexed strategy to simultaneously target carotenoid biosynthesis, turnover, and stable storage for carotenoid biofortification in crop seeds.

Download Full-text

Genetic analysis of grain yield and agronomic traits of early provitamin A quality protein maize inbred lines in contrasting environments

The Journal of Agricultural Science ◽

10.1017/s0021859619000753 ◽

2019 ◽

Vol 157 (5) ◽

pp. 413-433 ◽

Cited By ~ 4

Author(s):

E. Obeng-Bio ◽

B. Badu-Apraku ◽

B. E. Ifie ◽

A. Danquah ◽

E. T. Blay ◽

...

Keyword(s):

Grain Yield ◽

Gene Action ◽

Agronomic Traits ◽

Inbred Lines ◽

Sub Saharan Africa ◽

Provitamin A ◽

Heterotic Group ◽

Quality Protein Maize ◽

Heterotic Groups ◽

Early Maturing

AbstractEarly-maturing provitamin A (PVA) quality protein maize (QPM) hybrids with combined drought and low soil nitrogen (low-N) tolerance are needed to address malnutrition and food security problems in sub-Saharan Africa (SSA). The current study's objectives were to (i) examine combining ability of selected early maturing PVA-QPM inbreds for grain yield and other agronomic traits under drought, low-N, optimal environments and across environments, (ii) determine gene action conditioning PVA accumulation under optimal environments, (iii) classify inbreds into heterotic groups and identify testers and (iv) assess yield and stability of hybrids across environments. Ninety-six hybrids generated from 24 inbred lines using the North Carolina Design II together with four commercial hybrid controls were evaluated under drought, low-N and optimal environments in Nigeria in 2016 and 2017. Fifty-four selected hybrids were assayed for PVA carotenoid and tryptophan content. Additive genetic effects were greater than non-additive effects for grain yield and most agronomic traits under each and across environments. The gene action conditioning accumulation of PVA carotenoids under optimal growing conditions followed a pattern similar to that of grain yield and other yield-related traits. The inbred lines were categorized into four heterotic groups consistent with the pedigree records and with TZEIORQ 29 identified as the best male and female tester for heterotic group IV. No tester was found for the other groups. Hybrid TZEIORQ 24 × TZEIORQ 41 was the highest yielding and most stable across environments and should be further tested for consistent performance for commercialization in SSA.

Download Full-text

Popping volume and grain yield in diallel set of popcorn inbred lines

Genetika ◽

10.2298/gensr0803249p ◽

2008 ◽

Vol 40 (3) ◽

pp. 249-260 ◽

Cited By ~ 2

Author(s):

Zorica Pajic ◽

Uros Eric ◽

Jelena Srdic ◽

Snezana Mladenovic-Drinic ◽

Milomir Filipovic

Keyword(s):

Grain Yield ◽

Analysis Of Variance ◽

Combining Ability ◽

Inbred Lines ◽

Gene Effects ◽

Additive Gene Effects ◽

Satisfactory Yield ◽

Genetic Components ◽

Additive Gene ◽

Superior Genotypes

Popping volume and yield are traits caused by several heredity factors. It is difficult to obtain superior genotypes for both traits but it is possible to develop genotypes with good popping volume and satisfactory yield. The hybrid ZPPL2 x ZPPL5 was superior in yield, heterosis and SCA for both yield and popping volume. As inbred ZPPL4 in all combinations has a good value for popping volume could be concluded that this inbred may be used as parent in further crosses. Analysis of variance of the combining ability indicating significant SCA effect for grain yield, and significant both GCA and SCA effects for popping volume. Therefore it can be stated that yield is influenced by non-additive and popping volume by both additive and non- additive gene effects. Analysis of variance of genetic components for popping volume indicates that the additive as well as dominant components significantly affected the inheritance of this trait in popcorn. The objective of this study was to evaluate heteorsis and combing ability for grain yield and popping volume in dialalel set of six maize inbred lines.

Download Full-text

Estimates of Combining Ability and Heterosis for Yield and Its Related Traits in Pearl Millet Inbred Lines under Downy Mildew Prevalent Areas of Senegal

International Journal of Agronomy ◽

10.1155/2018/3439090 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Ghislain Kanfany ◽

Amadou Fofana ◽

Pangirayi Tongoona ◽

Agyemang Danquah ◽

Samuel Offei ◽

...

Keyword(s):

Grain Yield ◽

Flowering Time ◽

Downy Mildew ◽

Plant Height ◽

Pearl Millet ◽

Smallholder Farmers ◽

Central Africa ◽

Inbred Lines ◽

Gene Effects ◽

Additive Gene

Pearl millet is an important cereal crop for smallholder farmers’ food security in West and Central Africa. However, its production has stagnated due to several factors such as the continuous use of local populations. A set of 17 inbred lines was crossed with Sosat C 88 and Souna 3 following a line × tester mating design. The F1 hybrids, their parents, and a check were evaluated in Bambey and Nioro research stations during the rainy season of 2017. Data on downy mildew incidence, plant height, flowering time, panicle length and diameter, productive tillers, thousand-grain weight, panicle, and grain yield were recorded. GCA and SCA mean squares were significant for most of the traits indicating that both additive and nonadditive gene effects were involved in the control of the inheritance of these traits. However, the contribution of GCA to total mean squares was higher than that of SCA for all the traits, providing that additive gene action was more important in their inheritance. The top-cross hybrid IBL155-2-1 × Sosat C 88 exhibited negative and significant SCA effects for downy mildew incidence, flowering time, and plant height. Lines IBL003-B-1, IBL091-1-1, IBL095-4-1, IBL110-B-1, and IBL 206-1-1 had positive GCA effects for grain yield and negative GCA effects for downy mildew, flowering time, and plant height. These lines can be used as parents to create synthetic varieties or hybrids.

Download Full-text