scholarly journals Grain-yield stability among tropical maize hybrids derived from doubled-haploid inbred lines under random drought stress and optimum moisture conditions

2018 ◽  
Vol 69 (7) ◽  
pp. 691 ◽  
Author(s):  
Julius Pyton Sserumaga ◽  
Yoseph Beyene ◽  
Kiru Pillay ◽  
Alois Kullaya ◽  
Sylvester O. Oikeh ◽  
...  

Drought is a devastating environmental stress in agriculture and hence a common target of plant breeding. A review of breeding progress on drought tolerance shows that, to a certain extent, selection for high yield in stress-free conditions indirectly improves yield in water-limiting conditions. The objectives of this study were to (i) assess the genotype × environment (GE) interaction for grain yield (GY) and other agronomic traits for maize (Zea mays L.) across East African agro-ecologies; and (ii) evaluate agronomic performance and stability in Uganda and Tanzania under optimum and random drought conditions. Data were recorded for major agronomic traits. Genotype main effect plus GE (GGE) biplot analysis was used to assess the stability of varieties within various environments and across environments. Combined analysis of variance across optimum moisture and random drought environments indicated that locations, mean-squares for genotypes and GE were significant for most measured traits. The best hybrids, CKDHH1097 and CKDHH1090, gave GY advantages of 23% and 43%, respectively, over the commercial hybrid varieties under both optimum-moisture and random-drought conditions. Across environments, genotypic variance was less than the GE variance for GY. The hybrids derived from doubled-haploid inbred lines produced higher GY and possessed acceptable agronomic traits compared with the commercial hybrids. Hybrid CKDHH1098 ranked second-best under optimum-moisture and drought-stress environments and was the most stable with broad adaptation to both environments. Use of the best doubled-haploids lines in testcross hybrids make-up, well targeted to the production environments, could boost maize production among farmers in East Africa.

Author(s):  
Trương Thị Hồng Hải ◽  
Nguyễn Thị Diệu Thể ◽  
Phan Thu Thảo

In order to establish the pure line of sponge gourd containing aroma feature, we selected the desirable inbred lines by using a self-pollinating method. The present study was investigated to estimate the morphological traits and fruit quality of 6 sponge gourd inbred lines which generated at 4th generation of an aroma Luffa accession B29 under plastic house conditions. The experiment was conducted in a randomized complete block design (RCBD) with three replications, from May to November in 2016. Five plants per replication were examined. The results indicated that all inbred lines could grow well under plastic house conditions. The inbred lines had the same stem and leaf traits; whereas fruit shape, skin color and fruit veins color were observed differently among inbred lines. The aromatic trait was retained in all inbred lines either before or after cooking. The high yield was found in lines BC1 and BC2 by 10.1 tons/ha and 10.7 tons/ha, respectively. These inbred lines should be examined in open field condition to confirm the presence of aromatic trait and yield potential before completion of the procedures for recognition of new Luffa varieties.  


Author(s):  
Camelia RACZ ◽  
Ioan HAS ◽  
Voichita HAS ◽  
Teodora ŞCHIOP ◽  
I COSTE

The maize is one of the most important crops in the world due to its high productivity and multiplexing usage in human nutrition, animal breeding and industry. The isonucleus inbred lines study has been initiated from the demand of clarifying if the cytoplasm source has a positive or negative influence on the corn cars, plants, grain traits and some maize cultural features. The research has been conducted in the experimental field provided by the Maize Breeding laboratory from ARDS Turda, ARDB Târgu-Mureş, ARDS Secuieni, ARDS Livada, ARDS Suceava in 2009. The cell nucleus transfer activity for 12 elite inbred lines on various cytoplasm types has begun in 1992 starting from the assumption that among cytoplasm of different origin could exist differences in the genetic value. The ultimate objective of breeding works is to obtain a higher grain yield and the yield quality to be at the desired level of farmers. For this reason it was studied the effect of different types of cytoplasm on grain yield, kernel dry matter at harvest and unbroken plants percentage at harvest, all these traits are important to achieve secure yield, mechanized harvestable. The kernel dry matter at harvest is one of the indicators of vegetation period, the most used in choice of early single crosses.


2000 ◽  
Vol 80 (4) ◽  
pp. 739-745 ◽  
Author(s):  
B. L. Duggan ◽  
D. R. Domitruk ◽  
D. B. Fowler

Crops produced in the semiarid environment of western Canada are subjected to variable and unpredictable periods of drought stress. The objective of this study was to determine the inter-relationships among yield components and grain yield of winter wheat (Triticum aestivum L) so that guidelines could be established for the production of cultivars with high yield potential and stability. Five hard red winter wheat genotypes were grown in 15 field trials conducted throughout Saskatchewan from 1989–1991. Although this study included genotypes with widely different yield potential and yield component arrangements, only small differences in grain yield occurred within trials under dryland conditions. High kernel number, through greater tillering, was shown to be an adaptation to low-stress conditions. The ability of winter wheat to produce large numbers of tillers was evident in the spring in all trials; however, this early season potential was not maintained due to extensive tiller die-back. Tiller die-back often meant that high yield potential genotypes became sink limiting with reduced ability to respond to subsequent improvements in growing season weather conditions. As tiller number increased under more favourable crop water conditions genetic limits in kernels spike−1 became more identified with yield potential. It is likely then, that tillering capacity per se is less important in winter wheat than the development of vigorous tillers with numerous large kernels spike−1. For example, the highest yielding genotype under dryland conditions was a breeding line, S86-808, which was able to maintain a greater sink capacity as a result of a higher number of larger kernels spike−1. It appears that without yield component compensation, a cultivar can be unresponsive to improved crop water conditions (stable) or it can have a high mean yield, but it cannot possess both characteristics. Key words: Triticum aestivum L., wheat, drought stress, kernel weight, kernel number, spike density, grain yield


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1625
Author(s):  
Innocent Iseghohi ◽  
Ayodeji Abe ◽  
Silvestro Meseka ◽  
Wende Mengesha ◽  
Melaku Gedil ◽  
...  

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.


Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 240 ◽  
Author(s):  
Zhixin Zhao ◽  
Kunhui He ◽  
Zhiqian Feng ◽  
Yanan Li ◽  
Liguo Chang ◽  
...  

To screen the desired criterion to identify desirable genotypes and select genotypes best suited to limited nitrogen availability in order to facilitate the practice of low-nitrogen-tolerant breeding in maize, the response of 31 maize inbred lines, containing four control inbred lines (PH6WC, PH4CV, Zheng58, and Chang7-2) and others selected from the Shaan A and Shaan B heterotic groups cultivated at Northwest A&F University (Yangling, Shaanxi, China), were evaluated. The experiment was conducted following a split plot design with two replications during three growing seasons (2015, 2016, and 2017) under both high nitrogen (HN) and low nitrogen (LN) conditions at the Yulin and Yangling in Shaanxi Province, China. Seven screening indices, based on grain yield under two contrasting nitrogen (N) conditions, the stress susceptibility index (SSI), yield stability index (YSI), mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI), harmonic mean (HM), and low nitrogen tolerance index (LNTI), were computed to assess the overall index that accurately screened the desirable genotypes. The results of the correlation analyses and principal component analysis showed that MP, GMP, HM and STI were correlated with grain yield significantly and positively under contrasting N conditions, and were able to accurately discriminate the desirable genotypes. Compared with the control inbred lines, many inbred lines selected from the Shaan A and Shaan B groups showed a higher LN tolerance. This shows that we can effectively improve the LN tolerance of maize inbred lines through LN screening. Based on the screening indices, the three-dimensional diagram and genotype and genotype × environment (GGE) biplots are agreed with this results, and we identified KA105, KB081, KA225, 91227, and 2013KB-47 as the desired genotypes that have the potential to be used to breed a high yield and stable hybrid.


Author(s):  
Avinash Kumar ◽  
Ashutosh Kumar ◽  
N. K. Singh ◽  
Rajesh Kumar ◽  
S. K. Singh ◽  
...  

In the present investigation, 10 parents and their 45 crosses (half diallel) along with 2 standard checks (Rajendra Nilam and Rajendra Mahsuri-1) were evaluated during Kharif, 2018 in Randomized Complete Block Design (RCBD) with 3 replications at Rice Farm Section, Dr. Rajendra Prasad Central Agricultural University (RPCAU), Pusa, Bihar. The objective of this study was to identify promising rice genotypes having desirable combination of morphological traits along with high grain iron and zinc content and high grain yield potential. The results of variability parameters indicated that ample amount of genetic variability was present for all the studied traits. Most of the traits showed high heritability coupled with high genetic advance indicating fruitfulness of selection for improvement of these traits. One genotype (P2×P7) with high grain iron (16.10 ppm) and grain zinc (26.40 ppm) content along with high yield (43.12 g/plant) was identified. Genotypes with high grain iron coupled with high grain yield (P7×P9, P8×P9, P5×P7 and P5×P9) and high  grain zinc content coupled with high grain yield (P4×P7, P9×P10, P8×P9 and P5×P7) were also identified. These promising genotypes identified can be used further in breeding programmes to obtain superior segregants with high grain micronutrient content and high grain yield.


Author(s):  
É. Nagy ◽  
Á. Szabó-Hevér ◽  
S. Lehoczki-Krsjak ◽  
C. Lantos ◽  
E. Kiss ◽  
...  

AbstractDrought stress is one of the major abiotic factors that significantly reduces wheat grain yield. Improving drought tolerance is a challenge that plant breeders are facing nowadays. In this study, our goal was to identify quantitative trait loci (QTL) in the Plainsman V./Cappelle Desprez doubled haploid (DH) population under drought induced as decreased irrigation (ds) and well-watered (ww) conditions in glasshouse. In total, 54 QTL were detected across the three years in two water regimes linked to 10 drought tolerance-related agronomic traits. Out of the detected QTL regions several have been previously reported. The QTL on chromosome 1A (wPt-744613-wPt-8016) related to thousand grain weight was detected in both ds and ww conditions, explaining the 12.7–17.4% of the phenotypic variance. QTL for grain yield was detected on chromosomes 1A, and 6B in the ds treatment. Numerous QTL was identified under both irrigation levels.


2021 ◽  
Vol 4 (3) ◽  
pp. 286-304
Author(s):  
Lemi Mideksa Yadesa ◽  
Sentayehu Alamerew ◽  
Berhanu Tadesse

In spite of the importance of quality protein maize to alleviate protein deficiency, almost all maize varieties cultivated in Ethiopia are normal maize varieties, which are devoid of lysine and tryptophan. Perusing the combining ability of QPM inbred for grain yield and its components is vital to design appropriate breeding strategies for the development of nutritionally enhanced maize cultivars. A line x tester analysis involving 36 crosses generated by crossing 9  elite maize inbred lines with 4 testers were evaluated for different desirable agronomic traits during the 2019 main season at BNMRC and JARC. The experiment was conducted using alpha lattice design with 3 replications. The objectives were to determine the combining ability of quality protein maize inbred lines, adapted to mid altitude agroecology of Ethiopia for agronomic traits. The crosses were evaluated in alpha lattice design replicated 3 times. Analyses of variances showed significant mean squares due to crosses for almost all the traits studied. GCA mean squares due to lines and testers were significant (P<0.05 or P<0.01) for most studied traits. SCA mean squares were also significant for most attributes across locations. The comparative importance of GCA and SCA variances observed in the current study for most studied traits indicated the preponderance of additive genetic variance in governing these attributes. Only L3 was the best general combiner for grain yield. Inbred line L3, for days to anthesis and L5 for days to silking had negative and significant GCA effects. L5 and L6 displayed negative and significant GCA effects for plant and ear height. Crosses, L2xT4, L3xT4, L4xT4, L5xT2, L6xT3, L7xT2, L9xT1 and L9xT4 were good specific combiners for grain yield. In general, these genotypes help as a source of promising alleles that could be used for forthcoming breeding work in the development of quality protein maize cultivars with desirable traits.


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