scholarly journals Performance Assessment of Drought Tolerant Maize Hybrids under Combined Drought and Heat Stress

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 274 ◽  
Author(s):  
Silvestro Meseka ◽  
Abebe Menkir ◽  
Bunmi Bossey ◽  
Wende Mengesha
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Sub Saharan Africa ◽  
Yield Reduction ◽  
Grain Yields ◽  
Maize Productivity ◽  
Drought Tolerant ◽  
Sub Saharan ◽  
Major Factors ◽  
Drought And Heat Stress

Drought and high temperature are two major factors limiting maize productivity in sub-Saharan Africa. An increase in temperature above 30 °C reduces yield by 1% under optimal rain-fed condition and by 1.7% under drought stress (DS) and up to 40% under combined drought and heat stress (DSHTS). Approaches that improve performance under the two stresses are essential to sustain productivity. The objectives of this study were to (i) assess the extent of variation in tolerance to DSHTS from among the existing best drought tolerant (DT) hybrids; (ii) examine the response patterns of the hybrids to DSHTS; (iii) identify traits that contributed to better performance under DSHTS; and (iv) select the best hybrids with tolerance to DSHTS stress. We evaluated 40 DT hybrids under DSHTS, DS, and well-watered (WW) conditions for three years. Highly significant (p < 0.001) differences were found among hybrids for grain yield and other traits. Moderately to low repeatability values were detected for grain yield under DS (0.63) and under DSHTS (0.48). Grain yield under DS was not correlated with grain yield under DSHTS (r = 0.29; p = 0.06), but it was correlated with grain yield under WW (r = 0.74; p < 0.001). Grain yield was strongly correlated with ears per plant, ear and pant aspects, days to anthesis and silking under both DS and DSHTS. Tassel blast accounted for 28% of the yield reduction under DSHTS. The top five DT hybrids produced 9 to 26% more grain yields than the best commercial hybrid. Three hybrids produced high grain yields under DTHTS and DS as well as under WW. These hybrids will be tested further in collaboration with partners for possible release.

scholarly journals Assessment of Genetic Diversity for Drought, Heat and Combined Drought and Heat Stress Tolerance in Early Maturing Maize Landraces

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 518 ◽  
Author(s):  
Nelimor ◽  
Badu-Apraku ◽  
Tetteh ◽  
N’guetta
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Drought Stress ◽  
Grain Yield ◽  
Yield Potential ◽  
Yield Reduction ◽  
International Institute ◽  
Improvement Program ◽  
Maize Varieties ◽  
Drought And Heat Stress

Climate change is expected to aggravate the effects of drought, heat and combined drought and heat stresses. An important step in developing ‘climate smart’ maize varieties is to identify germplasm with good levels of tolerance to the abiotic stresses. The primary objective of this study was to identify landraces with combined high yield potential and desirable secondary traits under drought, heat and combined drought and heat stresses. Thirty-three landraces from Burkina Faso (6), Ghana (6) and Togo (21), and three drought-tolerant populations/varieties from the Maize Improvement Program at the International Institute of Tropical Agriculture were evaluated under three conditions, namely managed drought stress, heat stress and combined drought and heat stress, with optimal growing conditions as control, for two years. The phenotypic and genetic correlations between grain yield of the different treatments were very weak, suggesting the presence of independent genetic control of yield to these stresses. However, grain yield under heat and combined drought and heat stresses were highly and positively correlated, indicating that heat-tolerant genotypes would most likely tolerate combined drought and stress. Yield reduction averaged 46% under managed drought stress, 55% under heat stress, and 66% under combined drought and heat stress, which reflected hypo-additive effect of drought and heat stress on grain yield of the maize accessions. Accession GH-3505 was highly tolerant to drought, while GH-4859 and TZm-1353 were tolerant to the three stresses. These landrace accessions can be invaluable sources of genes/alleles for breeding for adaptation of maize to climate change.

scholarly journals Genetic Analysis of Early White Quality Protein Maize Inbreds and Derived Hybrids under Low-Nitrogen and Combined Drought and Heat Stress Environments

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2596
Author(s):  
Olatunde A. Bhadmus ◽  
Baffour Badu-Apraku ◽  
Oyenike A. Adeyemo ◽  
Adebayo L. Ogunkanmi
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Grain Yield ◽  
Gene Action ◽  
Sub Saharan Africa ◽  
Quality Protein Maize ◽  
Additive Gene Action ◽  
Additive Gene ◽  
Drought And Heat Stress ◽  
Low Nitrogen

An increase in the average global temperature and drought is anticipated in sub-Saharan Africa (SSA) as a result of climate change. Therefore, early white quality protein maize (QPM) hybrids with tolerance to combined drought and heat stress (CDHS) as well as low soil nitrogen (low-nitrogen) have the potential to mitigate the adverse effects of climate change. Ninety-six early QPM hybrids and four checks were evaluated in Nigeria for two years under CDHS, low-nitrogen, and in optimal environments. The objectives of this study were to determine the gene action conditioning grain yield, assess the performance of the early QPM inbred lines and identify high yielding and stable QPM hybrids under CDHS, low-nitrogen and optimal environment conditions. There was preponderance of the non-additive gene action over the additive in the inheritance of grain yield under CDHS environment conditions, while additive gene action was more important for grain yield in a low-nitrogen environment. TZEQI 6 was confirmed as an inbred tester under low N while TZEQI 113 × TZEQI 6 was identified as a single-cross tester under low-nitrogen environments. Plant and ear aspects were the primary contributors to grain yield under CDHS and low-nitrogen environments. TZEQI 6 × TZEQI 228 and the check TZEQI 39 × TZEQI 44 were the highest yielding under each stress environment and across environments. Hybrid TZEQI 210 × TZEQI 188 was the most stable across environments and should be tested on-farm and commercialized in SSA.

scholarly journals Heat Stress Effect on the Grain Yield of Three Drought-Tolerant Maize Varieties under Varying Growth Conditions

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1532
Author(s):  
Uchechukwu Paschal Chukwudi ◽  
Funso Raphael Kutu ◽  
Sydney Mavengahama
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Maize Yield ◽  
Growth Conditions ◽  
Grain Weight ◽  
Sub Saharan Africa ◽  
Stress Effect ◽  
Grain Number ◽  
Drought Tolerant ◽  
Maize Varieties

A rise in global temperature will reduce maize yield, particularly in Africa, where maize is a staple food. Therefore, improving maize yield under heat stress will promote food security in the region. The objective of this study was to assess the influence of heat stress on the grain yield of drought-tolerant maize varieties under varied growth conditions. The experimental design used was a 2 × 3 × 3 × 2 factorial fitted into a completely randomized design with four replications. The factors were heat stress, maize variety, soil amendment, and soil type. The results showed a better yield from sandy clay loam over loamy sand soil. Varieties WE5323 and ZM1523 amended with poultry manure gave the best yield under the non-heat and heat-stressed environments, respectively. Heat stress reduced the cob weight, grain weight, grain number, and stover dry weight by 64, 73, 69, and 23%, respectively. Grain number, grain weight, and cob weight were the most informative yield attributes in this study and should be considered in a maize selection program. The ranking for the maize varieties was WE5323 > ZM1523 > WE3128. Drought-tolerant maize varieties can be useful in heat stress mitigation. This information is useful for the simulation of maize yields for heat stress-prone areas in Sub-Saharan Africa.

scholarly journals Combining Ability of Early-Maturing Yellow Maize Inbreds under Combined Drought and Heat Stress and Well-Watered Environments

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1585
Author(s):  
Laouali M. Nasser ◽  
Baffour Badu-Apraku ◽  
Vernon E. Gracen ◽  
Hortense N. A. Mafouasson
Keyword(s):  
Heat Stress ◽  
Grain Yield ◽  
Combining Ability ◽  
Selection Index ◽  
Climatic Conditions ◽  
Sub Saharan Africa ◽  
Yield Potential ◽  
Early Maturing ◽  
Maize Inbreds ◽  
Drought And Heat Stress

Grain-yield potential of maize (Zea mays L.) is limited by the harsh climatic conditions during dry seasons in the savanna of sub-Saharan Africa (SSA). One hundred and five hybrids derived from diallel crosses involving 15 early-maturing yellow maize inbreds were screened under combined drought and heat stress (CDHS) and well-watered (WW) conditions at four locations representative of the dry savannas of Niger, 2012–2014. The objective of the study was to examine the general combining ability (GCA) effects of the inbred lines and specific combining ability (SCA) of the crosses under CDHS and WW environments, assess yield and stability of the derived hybrids under contrasting environments and investigate inter-relationships among traits of the hybrids under contrasting environments. GCA and SCA effects for grain yield and other measured traits were significant, with preponderance of GCA effects over SCA effects under both the CDHS and WW environments. Inbred ENT 13 possessed positive and significant GCA effects for grain yield under both CDHS and WW environments indicating that the inbred could be used for developing outstanding hybrids with good levels of tolerance to CDHS. This also implied that the inbred line could serve as invaluable genetic resource for introgression of favorable alleles into tropical early-maturing maize populations for accelerated genetic gains from selection for improved grain yield. Hybrids ENT 13 × TZEI 167 and TZEI 157 × ENT 13 were the most stable and among the highest yielding hybrids across research environments. These outstanding hybrids could be tested extensively for commercialization in SSA to improve food security. Plant and ear aspects and days to 50% silking could be combined with grain yield in a selection index for improvement of yield under CDHS without yield penalties under WW environments.

scholarly journals Combining ability and performance of extra-early maturing yellow maize inbreds in hybrid combinations under drought and rain-fed conditions

2017 ◽  
Vol 155 (10) ◽  
pp. 1520-1540
Author(s):  
I. C. AKAOGU ◽  
B. BADU-APRAKU ◽  
V. O. ADETIMIRIN
Keyword(s):  
Combining Ability ◽  
Central Africa ◽  
Sub Saharan Africa ◽  
Yield Reduction ◽  
Heterotic Groups ◽  
Drought Tolerant ◽  
Additive Gene ◽  
West And Central Africa ◽  
Sub Saharan ◽  
And Performance

SUMMARYMaize (Zea mays L.) is a major staple food and cash crop in sub-Saharan Africa (SSA). However, its production and productivity are severely constrained by drought. A total of 120 single-cross hybrids and an open-pollinated control variety were evaluated for 2 years at two locations under managed drought and rain-fed conditions in Nigeria. The objective of the present study was to assess their performance, classify them into distinct heterotic groups and identify promising hybrids for commercialization in the West and Central Africa sub-region. General combining ability and specific combining ability mean squares were highly significant for grain yield and other traits under the research environments. However, there was a preponderance of additive gene action over non-additive. Only six out of 39 inbreds were classified into distinct heterotic groups by the testers. The highest-yielding drought-tolerant hybrid, TZEEI 102 × TZEEI 95, out-yielded the open-pollinated control variety by 43·70%. The average yield reduction under drought was 54·90% of the yield under rain-fed conditions. The hybrids TZEEI 81 × TZEE1 79, TZEEI 100 × TZEEI 63 and TZEEI 64 × TZEEI 79 were the highest-yielding and most stable across environments. These outstanding drought-tolerant hybrids, which are also resistant to Striga, have the potential to contribute to food security and increased incomes in SSA and should be tested extensively on-farm and commercialized.

scholarly journals Drivers of Labour Productivity in Flower Farms in Naivasha, Kenya

2017 ◽  
Vol 6 (4) ◽  
pp. 117
Author(s):  
Jared Isaboke Mose
Keyword(s):  
Survey Design ◽  
Labor Union ◽  
Labour Productivity ◽  
Sampling Technique ◽  
Sub Saharan Africa ◽  
Export Market ◽  
Skills Acquisition ◽  
Sub Saharan ◽  
Ict Infrastructure ◽  
Major Factors

Although Kenya is the most successful producer and exporter of fresh produce and flowers in sub-Saharan Africa, other countries both in Africa and elsewhere, offer strong competition that could erode export market share in future. Increased labor productivity is crucial for Kenya’s competitiveness. This study aimed at examining the key drivers of labour productivity in flower farms in Naivasha, Kenya. Descriptive survey design was employed and stratified proportionate random sampling technique used to select 381 respondents from who data was collected using a questionnaire. A log-linearized Cobb-Douglas model was used examine determinants of labour productivity. The results showed that workers’ participation in Labor unions, Information & Communication Technology and workers’ skills acquired through training were the major factors that determined labour productivity by 35.4 percent, 19 percent and 14.7 percent respectively. While worker’s wage increase and tools used by a worker influenced labour productivity by 9 percent and 11.4 percent respectively. Worker’s level of education and worker’s experience also increased labour productivity by 5.1 percent and 4 percent respectively. The study recommends that; the Kenyan government should give special attention to education to produce skilled and innovative workers. Flower Farms should invest more in training of workers to acquire relevant skills, acquisition of appropriate tools; improve ICT infrastructure and support labor union in the flower farms.

scholarly journals Effect of Terminal High Temperature Imposed by Late Sowing on Phenological Traits of Wheat

2015 ◽  
Vol 18 (1) ◽  
pp. 13-25
Author(s):  
M Ilias Hossain ◽  
MRI Mondal ◽  
MJ Islam ◽  
MA Hakim ◽  
MK Sultan
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Yield ◽  
Stress Condition ◽  
High Temperature Stress ◽  
Yield Reduction ◽  
Stressed Condition ◽  
New Varieties ◽  
Heat Stress Condition ◽  
Late Sowing

Phenological performance in relation to yield of wheat genotypes; BARI Gom 26, BAW 1051, BARI Gom 27 and BARI Gom 28 were evaluated under normal and heat stress environments. One irrigated timely sowing (ITS) and three irrigated late sowings (ILS) were imposed to provide terminal high temperature over the tested genotypes. The ITS was November 25 and three ILS were December 10, December 25 and January 10. In heat stress condition, the genotypes phased a significant level of high temperature stress which affected on phenological stage and yield compared to ITS. In ITS situation, days to anthesis and booting decreased in heat stress condition regardless the cultivars. The phenological characteristics under heat stressed condition led the wheat cultivars to significantly lower grain yield as compared to normal condition. In heat stress situations (Dec 10–Jan 10), the average grain yield was reduced by12.8 -39.8 % in BARI Gom 26, 14.4-29.7% in BAW 1051, 11.5-26.5% in BARI Gom 27 and 17.4-25.6 % in BARI Gom 28 in both the season. It was also observed that grain yield was found to be reduced by about 7.7-15.4% in BARI Gom 26, 9.4-15.7 % in BAW 1051, 9.4-12.4% in BARI Gom 27 and 9.7-12.0% in BARI Gom 28 from ITS for each 1°C rise in average mean air temperature during booting to maturity. On the other hand, reduction percent were less for the new varieties. Grain yield reduction was about 1.4 - 2.65% in BARI Gom 28, 0.1-6.7 % in BARI Gom 27 and 1.7-6.0% in BAW 1051.Bangladesh Agron. J. 2015, 18(1): 13-25

scholarly journals Lipid Peroxidation and Chlorophyll Fluorescence of Photosystem II Performance during Drought and Heat Stress is Associated with the Antioxidant Capacities of C3 Sunflower and C4 Maize Varieties

2020 ◽  
Vol 21 (14) ◽  
pp. 4846
Author(s):  
Dilek Killi ◽  
Antonio Raschi ◽  
Filippo Bussotti
Keyword(s):  
Lipid Peroxidation ◽  
Antioxidant Activity ◽  
Heat Stress ◽  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Membrane Damage ◽  
Drought Tolerant ◽  
Maize Varieties ◽  
Catalase Peroxidase ◽  
Drought And Heat Stress

Agricultural production is predicted to be adversely affected by an increase in drought and heatwaves. Drought and heat damage cellular membranes, such as the thylakoid membranes where photosystem II occurs (PSII). We investigated the chlorophyll fluorescence (ChlF) of PSII, photosynthetic pigments, membrane damage, and the activity of protective antioxidants in drought-tolerant and -sensitive varieties of C3 sunflower and C4 maize grown at 20/25 and 30/35 °C. Drought-tolerant varieties retained PSII electron transport at lower levels of water availability at both temperatures. Drought and heat stress, in combination and isolation, had a more pronounced effect on the ChlF of the C3 species. For phenotyping, the maximum fluorescence was the most effective ChlF measure in characterizing varietal variation in the response of both species to drought and heat. The drought-tolerant sunflower and maize showed lower lipid peroxidation under drought and heat stress. The greater retention of PSII function in the drought-tolerant sunflower and maize at higher temperatures was associated with an increase in the activities of antioxidants (glutathione reductase, superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase), whereas antioxidant activity declined in the drought-sensitive varieties. Antioxidant activity should play a key role in the development of drought- and heat-tolerant crops for future food security.

Evaluation of cowpea (Vigna unguiculata (L.) Walp.) germplasm lines for tolerance to drought

2012 ◽  
Vol 10 (3) ◽  
pp. 171-176 ◽  
Author(s):  
Christian A. Fatokun ◽  
Ousmane Boukar ◽  
Satoru Muranaka
Keyword(s):  
Drought Tolerance ◽  
Sub Saharan Africa ◽  
Grain Legume ◽  
International Institute ◽  
Breeding Lines ◽  
Germplasm Collections ◽  
Legume Crop ◽  
Drought Tolerant ◽  
Cowpea Varieties ◽  
Sub Saharan

Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis, the bulk is produced and consumed. The dry savanna area of SSA is where cowpea is mostly grown under rain-fed conditions. The crop is therefore prone to drought which may occur early, mid and/or late in the cropping season. Compared with many other crops, cowpea is drought tolerant, even though drought is still a major constraint limiting its productivity in SSA. Increasing the level of drought tolerance in existing cowpea varieties grown by farmers would enable them to obtain more and stable yield from their cowpea fields. As a first step towards enhancing drought tolerance in existing cowpea varieties, 1288 lines were selected randomly from cowpea germplasm collections maintained at the International Institute of Tropical Agriculture, and evaluated for their drought tolerance at Ibadan. Drought was imposed by withdrawal of irrigation from 5 weeks after sowing. On average, drought reduced the number of days to flower by 12 d, and the mean grain yield per plant was also reduced by 67.28%. A few of the cowpea lines stayed green for up to 6 weeks after irrigation was stopped, even though some of these produced no pods when the study was terminated. Further evaluation in the screenhouse of 142 selected drought-tolerant lines helped to identify six lines that could be potential parents for developing breeding lines with enhanced drought tolerance.

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