scholarly journals Stacking Tolerance to Drought and Resistance to a Parasitic Weed in Tropical Hybrid Maize for Enhancing Resilience to Stress Combinations

2020 ◽  
Vol 11 ◽  
Author(s):  
Abebe Menkir ◽  
José Crossa ◽  
Silvestro Meseka ◽  
Bunmi Bossey ◽  
Oyekunle Muhyideen ◽  
...  
Keyword(s):  
Parasitic Weed ◽  
Hybrid Maize ◽  
Stress Combinations

Hybrid maize breeding with doubled haploids: Comparison between selection criteria

2006 ◽  
Vol 54 (3) ◽  
pp. 343-350 ◽  
Author(s):  
C. F. H. Longin ◽  
H. F. Utz ◽  
A. E. Melchinger ◽  
J.C. Reif
Keyword(s):  
Selection Criteria ◽  
Doubled Haploids ◽  
Optimum Allocation ◽  
Finite Sample ◽  
Sample Sizes ◽  
Maize Breeding ◽  
Selection Gain ◽  
Breeding Programmes ◽  
Hybrid Maize ◽  
Breeding Resources

The optimum allocation of breeding resources is crucial for the efficiency of breeding programmes. The objectives were to (i) compare selection gain ΔGk for finite and infinite sample sizes, (ii) compare ΔGk and the probability of identifying superior hybrids (Pk), and (iii) determine the optimum allocation of the number of hybrids and test locations in hybrid maize breeding using doubled haploids. Infinite compared to finite sample sizes led to almost identical optimum allocation of test resources, but to an inflation of ΔGk. This inflation decreased as the budget and the number of finally selected hybrids increased. A reasonable Pk was reached for hybrids belonging to the q = 1% best of the population. The optimum allocations for Pk(q) and ΔGkwere similar, indicating that Pk(q) is promising for optimizing breeding programmes.

Effect of Integrated Nutrient Management Practices on Growth and Development of Hybrid Maize Cultivar HQPM 1 in Mid-Hills of Meghalaya

2017 ◽  
Vol 4 (03) ◽  
Author(s):  
SAMBORLANG K. WANNIANG ◽  
A. K. SINGH
Keyword(s):  
Dry Matter ◽  
Management Practices ◽  
Nutrient Management ◽  
Dry Matter Accumulation ◽  
Integrated Nutrient Management ◽  
Graduate Studies ◽  
Green Manuring ◽  
Maize Cultivar ◽  
Significant Difference ◽  
Hybrid Maize

A field experiment was conducted during kharif 2011 on experimental farm of the College of Post Graduate Studies (CAU–Imphal), Umiam (Meghalaya) to evaluate the effect of integration of green manuring, FYM and fertilizers as integrated nutrient management (INM) practices on growth and developmental behaviour of quality protein maize cultivar QPM 1. The data revealed that comparatively higher amount of primary nutrients were added in green manured maize plots in comparison to non green manured treatments. Green manuring also left a positive response on plant height, CGR, RGR leaf area, and dry matter accumulation in plants though the difference between green manured and non-green manured treatments was at par. Treatments 75 % RDF + 5 t FYM ha-1, 50 % RDF + 7.5 t FYM ha-1, 100 % RDF ha-1 and 75 % RDF + 2.5 t FYM ha-1 recorded significantly higher values of all the above said growth parameters over 50 % RDF + 5 t FYM ha-1 and control treatments. At all stages of observations, the maximum dry matter was associated with RDF (recommended doses of fertilizers) which was at par with 75 % RDF + 5 t FYM ha-1, but significantly higher over the plant dry weight recorded from all remaining treatments. A Significant difference in CGR at 30 – 60 and 60 – 90 DAS stage and in RGR at 90 DAS - harvest stage was observed due to various combinations of recommended dose of fertilizer with different doses of FYM. Number of days taken to attain the stages of 50% tasselling, silking and maturity did not differ significantly due to green manuring. However, treatment 75 % RDF + 5 t FYM ha-1 took significantly lesser number of days for these stages than other treatment combinations. The superiority of the treatment 75 % RDF + 5 t FYM ha-1 indicated a possibility of substituting 25% of RDF with 5 t FYM ha-1 without any loss in dry matter accumulation in plants of the quality protein hybrid maize in mid-hill ecosystems of Meghalaya.

scholarly journals Selection Signatures Underlying Dramatic Male Inflorescence Transformation During Modern Hybrid Maize Breeding

Genetics ◽  
2018 ◽  
Vol 210 (3) ◽  
pp. 1125-1138 ◽  
Author(s):  
Joseph L. Gage ◽  
Michael R. White ◽  
Jode W. Edwards ◽  
Shawn Kaeppler ◽  
Natalia de Leon
Keyword(s):  
Selection Signatures ◽  
Maize Breeding ◽  
Male Inflorescence ◽  
Hybrid Maize

scholarly journals Crop and Residue Management Improves Productivity and Profitability of Rice–Maize System in Salt-Affected Rainfed Lowlands of East India

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2019
Author(s):  
Sukanta K. Sarangi ◽  
Sudhanshu Singh ◽  
Ashish K. Srivastava ◽  
Madhu Choudhary ◽  
Uttam K. Mandal ◽  
...  
Keyword(s):  
Soil Salinity ◽  
Crop Residues ◽  
Dry Season ◽  
Residue Management ◽  
Rice Grain ◽  
Rice Varieties ◽  
Available N ◽  
Cropping Intensity ◽  
Hybrid Maize ◽  
N Requirement

This study was conducted over 3 years in a salt-affected coastal rainfed lowland ecosystem. Farmers most commonly grow tall rice varieties in the wet season to cope with flash and/or stagnant floods, leading to large amounts of rice residue production. Most of the land remains fallow during the dry season because of increased salinity and scarcity of freshwater for irrigation. The study aims to provide options for increasing cropping intensity through management of crop residues (CR) and soil salinity, conservation of soil moisture, and reduction in production cost. The rice–maize rotation was assessed with rice as the main plot as (1) puddled transplanted rice (PTR) with CR of both rice and maize removed, (2) PTR and 40% CR of both crops retained, (3) dry direct-seeded rice (DSR) with CR of both crops removed, and (4) DSR with 40% CR of both crops retained. Maize in the dry season was supplied with different N levels as sub-plots—control (0 kg N ha−1), 80, 120, and 160 kg N ha−1. DSR, when combined with CR retention (DSR + R), reduced soil salinity. The increase in rice grain yield with CR retention (observed in second and third years) and crop establishment (higher in DSR versus PTR in the third year) was 16 and 24%, respectively. The cost of production increased by 17% (USD 605 ha−1) in PTR compared with DSR (USD 518 ha−1). CR retention reduced irrigation water requirement by 37% and N requirement by 40 kg ha−1 for hybrid maize. When CR was removed (−R), the N requirement for hybrid maize increased to 160 kg N ha−1 compared to when it was partially (40%) retained, where the requirement was 120 kg ha−1 with similar yields. Available N was highest under DSR + R (314 kg ha−1) and lowest under PTR − R (169 kg ha−1), and it also increased with increasing N application up to 120 kg ha−1 (+R) and 160 kg ha−1 (−R). The results of the study hold promise for increasing cropping intensity and farmers’ incomes, with broader implications for increasing productivity on about 2.95 million hectares currently under a rice–fallow system in eastern India, and in coastal areas affected by similar conditions in South and Southeast Asia.

scholarly journals Rural Roads Are Paving the Way for Land-Use Intensification in the Uplands of Laos

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 330
Author(s):  
Jean-Christophe Castella ◽  
Sonnasack Phaipasith
Keyword(s):  
Land Use ◽  
Management Practices ◽  
Management Strategies ◽  
Farming Systems ◽  
Long Term Effects ◽  
Group Discussions ◽  
Rural Roads ◽  
External Resources ◽  
Hybrid Maize ◽  
The Impact

Road expansion has played a prominent role in the agrarian transition that marked the integration of swidden-based farming systems into the market economy in Southeast Asia. Rural roads deeply altered the landscape and livelihood structures by allowing the penetration of boom crops such as hybrid maize in remote territories. In this article, we investigate the impact of rural road developments on livelihoods in northern Laos through a longitudinal study conducted over a period of 15 years in a forest frontier. We studied adaptive management strategies of local stakeholders through the combination of individual surveys, focus group discussions, participatory mapping and remote-sensing approaches. The study revealed the short-term benefits of the maize feeder roads on poverty alleviation and rural development, but also the negative long-term effects on agroecosystem health and agricultural productivity related to unsustainable land use. Lessons learnt about the mechanisms of agricultural intensification helped understanding the constraints faced by external interventions promoting sustainable land management practices. When negotiated by local communities for their own interest, roads may provide livelihood-enhancing opportunities through access to external resources, rather than undermining them.

Pollen Control During Transgenic Hybrid Maize Development in Mexico

Crop Science ◽  
1998 ◽  
Vol 38 (6) ◽  
pp. 1597-1602 ◽  
Author(s):  
M. C. Garcia ◽  
J. M. Figueroa ◽  
R. L. Gomez ◽  
R. Townsend ◽  
J. Schoper
Keyword(s):  
Hybrid Maize

scholarly journals Trehalose Protects Maize Plants from Salt Stress and Phosphorus Deficiency

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 568
Author(s):  
Md. Motiar Rohman ◽  
Md. Robyul Islam ◽  
Mahmuda Binte Monsur ◽  
Mohammad Amiruzzaman ◽  
Masayuki Fujita ◽  
...  
Keyword(s):  
Glutathione Peroxidase ◽  
Root Length ◽  
Phosphorus Deficiency ◽  
Monodehydroascorbate Reductase ◽  
Maize Seedlings ◽  
Combined Stress ◽  
Ros Scavenging ◽  
Sod Activity ◽  
Maize Varieties ◽  
Hybrid Maize

This study is undertaken to elucidate the role of trehalose (Tre) in mitigating oxidative stress under salinity and low P in maize. Eight-day-old maize seedlings of two maize varieties, BARI Hybrid Maize-7 and BARI Hybrid Maize-9, were subjected to salinity (150 mM NaCl), low P (5 µM KH2PO4) and their combined stress with or without 10 mM Tre for 15 d. Salinity and combined stress significantly inhibited the shoot length, root length, and root volume, whereas low P increased the root length and volume in both genotypes. Exogenous Tre in the stress treatments increased all of the growth parameters as well as decreased the salinity, low P, and combined stress-mediated Na+/K+, reactive oxygen species (ROS), malondialdehyde (MDA), lipoxygenase (LOX) activity, and methylglyoxal (MG) in both genotypes. Individually, salinity and low P increased superoxide dismutase (SOD) activity in both genotypes, but combined stress decreased the activity. Peroxidase (POD) activity increased in all stress treatments. Interestingly, Tre application enhanced the SOD activity in all the stress treatments but inhibited the POD activity. Both catalase (CAT) and glutathione peroxidase (GPX) activity were increased by saline and low P stress while the activities inhibited in combined stress. Similar results were found for ascorbate peroxidase (APX), glutathione peroxidase (GR), and dehydroascorbate reductase (DHAR) activities in both genotypes. However, monodehydroascorbate reductase (MDHAR) activity was inhibited in all the stresses. Interestingly, Tre enhanced CAT, APX, GPX, GR, MDHAR, and DHAR activities suggesting the amelioration of ROS scavenging in maize under all the stresses. Conversely, increased glyoxalase activities in saline and low P stress in BHM-9 suggested better MG detoxification system because of the down-regulation of glyoxalase-I (Gly-I) activity in BHM-7 in those stresses. Tre also increased the glyoxalase activities in both genotypes under all the stresses. Tre improved the growth in maize seedlings by decreasing Na+/K+, ROS, MDA, and MG through regulating antioxidant and glyoxalase systems.

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