The Influence of Water Stress on Yield and Related Characteristics in Inbred Quality Protein Maize Lines and Hybrid Progeny (original) (raw)
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Water Stress, 2012
Water stress is one of the factors most frequently limiting maize production, food security, and economic growth in sub-Saharan Africa. The unprecedented combination of climatic risk, declining soil fertility, the need to expand food production into more marginal areas as population pressure increases, high input costs, extreme poverty, and unavailability of credit systems, have resulted in small holder farmers in southern and eastern Africa producing maize in extremely low-input/low risk systems (Banziger and Diallo, 2004). As a consequence, crop yields are falling to very low levels and food insecurity is widespread amongst agricultural communities (Kamara et al., 2004). The development of maize germplasm able to tolerate water stress is crucial if the productivity of maize based farming systems is to be sustained or increased (Betran et al., 2003). Maize genotypes perform differently under water stress conditions due to the existence of genetic variability for tolerance to stress (
Journal of Crop Improvement, 2017
Early-maturing maize (Zea Mays L.) germplasm developed from diverse sources has the potential for use in developing maize hybrids suitable for increasing maize production in the dry ecologies of eastern Africa. A diallel study was conducted to estimate general combining ability (GCA) of 12 early-maturing maize inbred lines, identify potential single-cross hybrids for use as parents, assess genetic diversity among the inbred lines, and relate genetic distance to specific combining ability (SCA) and hybrid performance. Sixty-six F 1 diallel hybrids were evaluated under optimal and drought stress conditions at four locations in Kenya and Uganda. The parental inbred lines were genotyped using 94 single nucleotide polymorphism (SNP) markers. Additive gene action was more important than nonadditive gene action for inheritance of grain yield (GY) under optimal conditions. However, nonadditive gene effects were more important in the inheritance of GY under drought and across all environments. Inbred lines CKL0722, VL058014, and CZL0724 were among the best with positive GCA effects for GY across both optimal and drought stress conditions. The correlation between SCA and both genetic distance and F 1 GY was significant under both drought stress and across all environments. Inbred lines with desirable GCA effects for GY and other agronomic traits and hybrids with good performance under both optimal and drought stress conditions are potential parents for development of various types of high-yielding, stress-tolerant, and early-maturing hybrids.
Maydica, 2014
Knowledge of the heterotic responses of elite adapted and exotic maize inbred lines can facilitate their utilization for population improvement and hybrid development. In the present study, a line x tester mating design was used to determine the combining ability of 20 elite drought-tolerant maize inbred lines developed at CIMMYT and IITA and to classify them into heterotic groups under diverse growing conditions. The 20 lines were crossed each with two inbred line testers representing the tropical and temperate heterotic pattern established in West and Cental Africa (WCA), to generate 40 testcrosses. A trial comprising the 40 testcrosses along with the cross between the two testers and three hybrid checks were evaluated at two environments in the dry season and at six environments in the rainy season. GCA effects were more important than SCA effects in controlling grain yield in both seasons. Two exotic lines in the dry season and four exotic lines in the rainy season had significantly positive GCA effects. Only EXL22 was identified as a superior line in the two seasons. Only two adapted lines had significantly positive GCA effects in either or both seasons while three adapted lines consistently had significantly negative GCA effects in both seasons. Hybrid between EXL22 and tester 9071 showed broad adaptation to all test environments. The two testers separated some of the lines into two main heterotic groups. the lines in each heterotic group and the good combiners will be utilized for developing populations for extracting new improved inbred lines.
Euphytica, 2014
Introduced maize (Zea mays L.) germplasm can serve as sources of favorable alleles to enhance performance in new maize varieties and hybrids under drought stress conditions. In the present study, the combining abilities of 12 exotic maize inbred lines from CIMMYT and 12 adapted maize inbred lines from IITA were studied for grain yield and other traits under controlled drought stress. The inbred lines from each institution were separated into groups using SSR-based genetic diversity and were intercrossed using a factorial mating scheme to generate 96 hybrids. These hybrids were evaluated under both controlled drought stress and well-watered conditions at Ikenne in Nigeria in 2010 and 2011. Average mean yields of hybrids under drought stress represented 23 % of the average yield of hybrids under full irrigation. General combining ability (GCA) effects accounted for 49-85 % of the observed variation for several traits recorded under both well-watered and drought stress conditions. Specific combining ability effects for grain yield, though positive in most hybrids, were not significant under drought stress conditions. All the twelve exotic and nine adapted lines had positive GCA effects (female, male, or both) for grain yield under either drought stress or full irrigation, or both environments. EXL03 and EXL15 that had positive and significant female and male GCA effects for grain yield under both environments can be used to improve their adapted counterparts for grain yield and drought tolerance. Normalized difference vegetation index had weak but significant correlation with grain yield.
Euphytica, 2017
Estimates of combining abilities and heterosis of inbred lines are imperative for selection of suitable parents of maize hybrids. This study examined the combining ability of 24 drought-tolerant maize inbred lines, 12 each from International Centre for Maize and Wheat Improvement (CIMMYT) and International Institute of Tropical Agriculture (IITA). The lines were allotted into six groups each comprising four lines. The four lines in one group were used as females and crossed to the four lines in another group as males in six different sets using a North Carolina Design II mating scheme to generate 96 hybrids. The hybrids were evaluated together with four checks across six environments in the rainforest and savannah agro-ecologies of Nigeria between 2011 and 2012. The parental inbred lines were also evaluated in separate trial in each location. Significant hybrids 9 environment interaction was observed for grain yield and other measured traits. GCA effects accounted for 83.3% of the variation for grain yield at Bagauda, 78.1% at Saminaka, and 77.7% at Ikenne. GCA also contributed 91.1 and 80.0% to the variation observed for plant height and ear aspect, respectively, across the environments. Significant SCA 9 environment interaction detected for grain yield suggests that hybrids were not stable across test environments. Prediction of grain yield in hybrids using midparent values resulted in a R 2 value of 0.13. Midparent heterosis for grain yield varied from 80 to 411%, with the top 36 hybrids recording[200%. Four CIMMYT (EXL02, EXL06, EXL04 and EXL16) and three IITA (ADL33, ADL41, and ADL32) inbred lines had positive and significant GCA effects for grain yield across environments. The novel alleles present in the CIMMYT lines will improve the adapted IITA germplasm in a new population for extracting new set of more productive inbred lines for developing adapted high yielding drought-tolerant maize hybrids.
Canadian Journal of Plant Science, 2011
Badu-Apraku, B. and Akinwale, R. O. 2011. Identification of early-maturing maize inbred lines based on multiple traits under drought and low N environments for hybrid development and population improvement. Can. J. Plant Sci. 91: 931–942. Drought and low nitrogen stresses are major limiting factors to maize (Zea mays L.) production and productivity in West and Central Africa. Studies were conducted from 2007 to 2009 at three locations in Nigeria under induced drought stress and low nitrogen conditions. The objective was to identify superior inbred lines for use as parents for hybrid production and for introgression into maize breeding populations. The inbreds TZEI 17, TZEI 13, TZEI 23, TZEI 2, TZEI 3, TZEI 22, TZEI 7, TZEI 11, and TZEI 8 were identified as the most promising parents under drought stress. Under low N, TZEI 7, TZEI 11, TZEI 2, TZEI 4, TZEI 10, TZEI 8, and TZEI 22 were selected. TZEI 11, TZEI 2, TZEI 8, and TZEI 22 had combined tolerance to drought stress and low N and...
Agronomy
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 x 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 abi...
Scientific Reports
Availability of multiple-stress tolerant maize is critical for improvement in maize production in West and Central Africa (WCA). A study was carried out to (i) assess a set of inbred lines for combining ability under stressed and optimal conditions, (ii) determine the performance of the testcrosses under different conditions, and (iii) identify outstanding hybrids across the conditions. Two hundred and five testcrosses were planted with five hybrid checks under Striga-infested, low soil nitrogen, drought and optimal conditions between 2015 and 2016 in Nigeria. The grain yield inheritance under optimal condition was largely regulated by additive gene effect whereas non-additive gene effects largely regulated grain yield under the three stresses. Four of the inbreds had significant positive general combining ability effects each under low N and drought, and three under Striga infestation for grain yield. The inbreds could be vital sources of beneficial alleles for development and impr...
Crop Science, 2003
to predict hybrid performance and the efficiency of pre-(Zea mays L.) lines and the correlation between genetic distance (GD) and hybrid performance would determine breeding strategies, diction was greater with crosses between inbred lines classify inbred lines, define heterotic groups, and predict future hybrid from the same heterotic group than in crosses between performance. The objectives of this study were to estimate (i) heterosis inbred lines from different heterotic groups (Melchand specific combining ability (SCA) for grain yield under stress and inger, 1999). Linkage disequilibrium between DNA non-stress environments; (ii) genetic diversity for restriction fragment markers and genes involved in the expression of target length polymorphisms (RFLPs) within a set of tropical lines; (iii) GD traits is required for GD and hybrid performance to be and classify the lines according to their GD; and (iv) correlation correlated. The effect of the population structure on between the GD and hybrid performance, heterosis, and SCA. Seventhe relationship between genetic distance and heterosis teen lowland, white tropical inbred lines were represented in a diallel was described by Charcosset and Essioux (1994). study. Inbred lines and hybrids were evaluated in 12 stress and non-Tropical maize is grown on approximately 45 million stress environments. The expression of heterosis was greater under drought stress and smaller under low N environments than under ha in lowland tropical environments (Pingali, 2001). Alnonstress environments. A set of DNA markers identifying 81 loci though hybrid development in tropical maize started was used to fingerprint the 17 lines. The level of genetic diversity was