Field Evaluation of Heat Stress-Resilient Maize Hybrids for Improved and Stable Maize Production in Nepal

Abstract

In recent years, National Maize Research Program (NMRP) aimed a paradigm shift from open-pollinated varieties (OPVs) towards hybrid maize to achieve self-sufficiency in maize for food, feed, and hybrid seed within the country. In this mission, it is necessary to identify and deploy high-yielding stress-resilient maize hybrids that can cope with climate change effects, including heat stress. Under the project “Heat Tolerant Maize for Asia (HTMA)”, NMRP introduced the hybrids that performed better in previous years in different environments from International Maize and Wheat Improvement Center (CIMMYT) Hyderabad for multilocation on-farm testing. Fifteen genotypes were evaluated at two locations, two sites in Madi, Chitwan, and one in Ghorahi, Dang, along with Rampur Hybrid-8 as a heat-tolerant check, and RML-86/RML-96 and RML-95/RML-96 as normal checks. Randomized complete block design (RCBD) was used with three replicates during the spring of 2016/17. Likewise, another 20 and 18 promising hybrids were demonstrated during the winter of 2016/17 and 2017/18, respectively, in different hybrid growing pockets considering a site – a replication. Grain yield and yield attributing traits at all locations were recorded. From the across-site data analysis, selected heat-tolerant hybrids from the experiment were CAH1432, ZH15405, ZH141592, and CAH1715 which were statistically at par with promising normal hybrid RML-86/RML-96 and superior to already released heat-tolerant Rampur Hybrid-8. In 2016/17, ZH138098, ZH1620, and VH121062 were farmers’ preferred heat-tolerant hybrids. In 2017/18, Rampur Hybrid-10, ZH141592, CAH1715, and ZH15440 were preferred by farmers. The selected bestbet are taken forward for official release/registration followed by commercialization through a public-private partnership with Nepali seed companies/cooperatives. SAARC J. Agric., 19(1): 27-43 (2021)

Varietal evaluation of hybrid maize in the summer and winter seasons in terai region of Nepal

“…The ear height ranged from 92-127cm and 136–164cm in winter and summer season respectively. Several researchers [ 7 , 13 , 14 , 15 , 36 ] reported plant architectural traits of maize within this range which supports current finding.…”

“…Anthesis silking interval between 2-4 days are found to have a positive effect on grain yield of maize i.e. ASI is negatively correlated to yield and a close gap in ASI has been reported in maize hybrid by several researchers [ 23 , 37 , 38 , 39 , 40 , 41 ]. The yield and its components showed dependence on the ASI [ 42 ].…”

“…After harvesting all the ears from each plot was collected, ear count was taken and later converted in hectare ( Equation 1 ) as suggested by Badu-Apraku et al. [ 12 ] which was also followed by others [ 7 , 8 , 13 , 14 , 15 , 16 ] in maize breeding program. Ears from tagged plants were taken and used for recording cob characteristics like Cob length (CL), Cob diameter (CD), Number of grains per row (NOGPR), and Number of rows per cob (NORPC).…”

Agro-Morphological Characterization and Estimation of Genetic Parameters of Spring Maize Hybrids in the Inner Plains of Far-West Nepal

“…e anthesis and silking days of spring maize are comparatively shorter than those of winter maize [7], where the average length varies from 100 to 111 days in anthesis and 102-11 days in silking. e ASI of heat resilient hybrids in the range of 2-4 days has been reported in chitwan and dang condition [16]. When maize is subjected to stress during flowering due to light, nutrients, drought, or long photoperiods, the duration of the ASI increases, which appears to be a general response by the plant to a reduction in photosynthate formed during this growth stage [5].…”

Agromorphological Characterization of Maize Hybrids and Estimation of Genetic Parameters in Mid-Hills of Far-West Nepal

“…Maize contributes one-fourth of total edible cereal grain production in Nepal but the production of maize per hectare of land is below average as compared to other developed nations [3]. In order to attain self-sufciency in maize for food, feed, and the hybrid seed inside the nation, the National Maize Research Program (NMRP) set out to pioneer a shift away from open-pollinated varieties (OPVs) toward hybrid maize [4]. As stated in National Seed Vision (NSV) and Agriculture Development Strategy, it is thought that the potential yield of maize cannot be realized alone by expanding farms, replacing them with modifed ones, and popularizing OPVs (ADS) [5,6].…”