scholarly journals HERITABILITY AND HETEROSIS OF GRAIN YIELD ON DOWNY MILDEW RESISTANCE (DMR) AND QUALITY PROTEIN MAIZE (QPM) INBREDS AND THEIR SINGLE CROSS HYBRIDS

Zuriat ◽  
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
D. Ruswandi ◽  
N. Wicaksana ◽  
M. Rachmadi ◽  
A. Ismail ◽  
D. Arief ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Downy Mildew ◽  
High Yield ◽  
Quality Protein Maize ◽  
Downy Mildew Resistance ◽  
Narrow Sense Heritability ◽  
Mildew Resistance ◽  
Single Cross ◽  
Single Cross Hybrids

Improvement of high yield maize cultivars possessing high quality of seed as showed by high lysine and tryptophan content must be fulfilled with resistance against downy mildew pathogen in any maize breeding program. A set of experiment to study genetic variability and to estimate both heritability and heterosis of important characters of grain yield on DMR and QPM lines has been conducted. Four downy mildew resistance (DMR) lines, i.e. Nei 9008, P 345, Ki 3, and MR 10; three quality protein maize (QPM) lines, including CML 161, CML 163, and CML 172; and their single cross hybrids formed based on line × tester mating design were used in the experiment. The following characters: height of the first ear, seeds number per row, seed weight per ear, and grain yield per plot showed broad genetic variability. Narrow sense heritability (hns) of grain yield and its components ranged from 0.01 to 0.71. Broad sense heritability (hbs), on the other hand, ranged from 0.20 to 0.74. It was found that hybrid derived from crossing between parental inbred lines possessing broad genetic background would express high heterosis.

scholarly journals Grain Yield Performance and Stability of Quality Protein Maize Single Cross Hybrids in Mid-altitude Environment in Uganda

2018 ◽  
Vol 10 (9) ◽  
pp. 55
Author(s):  
J. Ayiga-Aluba ◽  
G. Asea ◽  
D. B. Kwemoi ◽  
G. Tusiime ◽  
R. Edema
Keyword(s):  
Grain Yield ◽  
Degrees Of Freedom ◽  
Principal Component ◽  
Yield Response ◽  
Average Score ◽  
Quality Protein Maize ◽  
Environment Interaction ◽  
Ecological Zones ◽  
Single Cross ◽  
Single Cross Hybrids

Stability in performance is important for determining adaptation and recommendation of pre-commercial crop varieties. This study was conducted with the following objectives: i) to determine stability of grain yield for 55 quality protein maize (QPM) single cross hybrids generated from 14 inbred lines ii) to determine the pattern of grouping of QPM hybrids and test environments based on grain yield response. The test hybrids were generated during the second season of 2015 and evaluated in three agro-ecological zones during the first season of 2016. Two checks were used: Longe 5D, a popular QPM hybrid and a top cross of Longe 5D with CML511. Additive main effects and multiplicative interaction (AMMI) and genotype and genotype by environment interaction (GGE) analyses were used to assess the stability of the hybrids. Results showed highly significant differences between genotypes, environments and GEI. The first principal component axis (IPCAI) was significant (p < 0.01) and accounted for 61.5% of the interaction effect. Both (IPCAI) and IPCAII) cumulatively contributed to entire degrees of freedom available for interaction component. Hybrid QPMSC-29 had the highest grain yield across environments. The AMMI biplot clearly depicted the genotypes on the bases of their adaptation patterns. Hybrids QPMSC-43, QPMSC-12, QPMSC-18 and QPMSC-29 were found to be more stable and responsive to favorable environments. Among them QPMSC-18 was more stable across locations. The AMMI biplot successfully identified 2 mega-environments as Namulonge and Bulindi in the first mega-environment with QPMSC-29 as the winning genotype and Masaka as the second mega-environment with QPMSC-10 as the winning genotypes. Hybrid, QPMSC-46 was an ideal genotype with above average score for grain yield. The single cross hybrids QPMSC-29, QPMSC-18 and QPMSC-10 were identified as stable yielder across environments in addition to higher yield. These hybrids can be recommended for all the three locations, for cultivation.

scholarly journals Combining ability analysis for yield and quality traits in single cross hybrids of quality protein maize (Zea mays L.) using diallel mating design

2017 ◽  
Vol 9 (3) ◽  
pp. 1760-1766
Author(s):  
Prashant Bisen ◽  
Amit Dadheech ◽  
Namrata Namrata ◽  
Avinash Kumar ◽  
Gurudatt Solanki ◽  
...  
Keyword(s):  
Grain Yield ◽  
Combining Ability ◽  
Quality Protein Maize ◽  
Quality Traits ◽  
Mating Design ◽  
Yield And Quality ◽  
Diallel Mating Design ◽  
Single Cross ◽  
Per Se ◽  
Single Cross Hybrids

Forty-five single-cross hybrids developed (in rabi 2014) from ten inbred lines of quality protein maize through diallel mating design along with four checks viz., Pratap QPM Hybrid- 1, Vivek QPM- 9, HQPM- 1 and HQPM-5 were evaluated in randomized block design with three replications for yield and quality traits during kharif-2014, to estimate the gca (general combining ability) of the parents and sca (specific combining ability) of hybrids considered for the development of high yielding varieties. The analysis of variance for combining ability revealed significant mean sum of squares due to gca and sca for all the traits, except mean sum of square due to gca for num-ber of grain rows per ear. Ratio of σ2 sca / σ 2 gca was greater than one for all the traits, thereby indicating the preponderance of non-additive gene effects in the expression of these traits. Inbred line P8 and P5 has been found good general combiner with highest magnitude of gca effects 10.46 and 8.89, respectively and high per se i.e. 52.33 g and 44.67 g, respectively for grain yield per plant and majority of traits. Hybrids P6xP8, P5xP8, P3xP5, P5xP7 and P1xP8 showed higher significant positive sca effects ranged from 25.66 to 34.59 along with good per se ranged from 98.00 to 107.67 g for grain yield per plant. These hybrids also exhibited significant positive sca effects for most of the yield and quality traits under study, indicating potential and may be used for exploiting hybrid vigour in in QPM hybrid breeding programmes.

scholarly journals PRELIMINARY STUDY ON THE HETEROTIC PATTERN OF TROPICAL QUALITY PROTEIN MAIZE (QPM) AND DOWNY MILDEW RESISTANCE (DMR) MAIZE INBREDS

Zuriat ◽  
2015 ◽  
Vol 16 (2) ◽  
Author(s):  
D. Ruswandi
Keyword(s):  
Small Group ◽  
Downy Mildew ◽  
Major Group ◽  
Annual Rainfall ◽  
Quality Protein Maize ◽  
Downy Mildew Resistance ◽  
Heterotic Groups ◽  
Mildew Resistance ◽  
Preliminary Study ◽  
Maize Inbreds

Exploration of heterotic patterns among maize inbreds has become important since it could provide information on which new germplasm could be used to improve base population in breeding program. This experiment was a preliminary study on the heterotic relationships between tropical quality protein maize (QPM) and downy mildew resistance (DMR) maize inbreds based on analysis on combining ability. Seven tropical maize inbreds were crossed in a line × tester. One commercial hybrid from Bisi Company, Bisi 2, was included for the evaluation of hybrids as check cultivar. The result revealed that two heterotic groups has been recognized, i.e., major group consisted of CML 161, CML 163, CML 172, Nei 9008, and P345. Whereas the small group contains MR 10 and Ki 3. The hybrids and their parental inbreds were evaluated in Jatinangor, Indonesia (753 m above sea level) in 2003 to 2004. The location of yield test has a humid climate with an annual rainfall of about 1925 mm. The field experiment was arranged in a randomize block design with two replications. The present study revealed two heterotic groups: major group involving CML 161, CML 163, CML 172, Nei 9008, and Ki 3; and small group containing MR 10 and P 345. Moreover, the major group can be divided into two subgroups involving all CML lines for the first subgroup and Nei 9008 and Ki 3 for the second subgroup.

Susceptibility of Hop Cultivars to Downy Mildew: Associations with Chemical Characteristics and Region of Origin

2016 ◽  
Vol 17 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Joanna L. Woods ◽  
David H. Gent
Keyword(s):  
United States ◽  
Downy Mildew ◽  
The United States ◽  
High Yield ◽  
Downy Mildew Resistance ◽  
Region Of Origin ◽  
Mildew Resistance ◽  
The United Kingdom ◽  
Pseudoperonospora Humuli ◽  
High Level

Hop downy mildew (caused by Pseudoperonospora humuli) is a yield-limiting disease in many hop-production regions of the world. In this research, 110 cultivars that are or were widely grown in the United States, Europe, or Australasia were evaluated in western Oregon over three years for their reaction to the shoot infection phase of downy mildew and vigor. There was a large range of downy mildew susceptibility and vigor amongst commercial cultivars, with some cultivars possessing a very high level of resistance. Overall, however, disease resistance and vigor were significantly greater in cultivars originating from Europe than those originating from the United States, Japan, and Australia/New Zealand. Amongst a subset of 79 cultivars, vigor was negatively correlated with levels, in cones, of cohumulone, a chemical constitute of bittering acids typically found in germplasm derived from North America. The generally poor vigor observed in cultivars derived outside of Europe likely is indicative of a lack of tolerance to the crown infection phase of the disease. Thus, the best sources of downy mildew resistance seems to be found in cultivars from the United Kingdom and continental Europe, and such cultivars are typically lower yielding and lack distinctive aroma and flavor characteristics presently desired by craft brewers. Introgression of downy mildew resistance into North American germplasm with high yield and desirable brewing characteristics is needed. Accepted for publication 3 March 2016. Published 7 March 2016.

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