Introduction

Maize (Zea mays L.) is the third important cereal crops after rice and wheat in the world. It has highest yield potential over other cereals and thus known as “queen of cereals” (Mahajan, Singh, Ambika Rajendran, & Kanya, 2012). Maize is one of the most versatile crops with wider adaptability in different agro ecologies. The global production of maize is 1.13 billion tons with productivity of 5.75 t ha^-1from the area of 197,185,936 ha (Fao, 2018). Maize is considered to be nutritious food and feed as it contains 72% starch, 10% protein, 4.8% oil, 9.5% fiber, 3% sugar and 1.7% ash (Chaudhary, 1983). Per capita maize consumption in Nepal is 98 g/person/day (Ranum, Pena-Rosas, & Garsia-Casal, 2014). Total quantity of maize requirement for food per year is around 2.9 million mt and the production was 2.283 million mt, hence the deficit was 0.67 million mt (Moad, 2015). The maize demand has been constantly growing by about 5% annually in the last decades (Sapkota and Pokhrel, 2013). Population of Nepal is growing annually at rate of 1.28% for next ten years (CBS, 2014). As a result of growing maize consuming population in the hills as well as increasing use of maize for feed in the rapidly expanding poultry and dairy sector, the demand for maize is increasing very fast but its production is growing slowly. 

1 Result

1.1 Biometric observation

1.1.1 Plant height

The plant height increased up to maturity and ranged from 19.04 to 195.95 cm (Table 1). Plant height was found non-significant up to 60 DAP and 90 DAP whereas it was significantly influenced by maize hybrids at 75 DAP and at harvest. The mean plant height at 45 DAP was recorded as 25.71 cm which increased to 54.7 cm at 60 DAP. At 75 DAP, plant height was significantly greater in P3522 (146.2 cm) which was statistically at par with P3396 (141.4 cm), X5 (125.5) and RML 95/96 (120.6 cm).10V10 showed lowest plant height with 107.1 cm which was statistically at par with RML 86/96 (116.9 cm).

Table 1 Plant height of maize as influenced by variety at Lamahi, Dang during spring, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance

The mean height at harvest was found to be 208.5 cm and was found to be significantly influenced by maize hybrids. At harvest, P3396 showed significantly higher plant height of 225.4 cm which was statistically at par with P3352 (220.6 cm) and X5 (216.3 cm), while both the Nepali genotypes RML 95/96 and RML 86/96 had 207.5 cm height at harvest.10V10 showed significantly lower plant height of 196.3 cm at harvest. 

1.1.2 Number of leaves

In this experiment, the mean value of number of leaves indicated that it increased from 30 DAP to 90 DAP and gradually decreased up to harvest stage (Table 2). The mean value of number of leaves at 30 DAP was 4.24 which ranged from 4.067 in 10V10 and P3522 to 4.533 in RML 86/96. The average number of leaves at 45 DAP was found to be 6.289 and ranged from 6 in RML 95/96 to 6.6 in P3522. At 60 DAP it increased to 8.29 and ranged from 7.53 in 10V10 to 8.87 in P3396. The number of leaves at 75 DAP was found to be 12.628 in this experiment and ranged from 12.133 in RML 95/96 to 13 in P3396. The average number of leaves increased to 14.49 in 90 DAP and ranged from 14.17 in RML 86/96 to 14,83 in 10V10. At harvest, the number of leaves decreased to 12.79 and ranged from 12.33 in RML 95/96 to 13.13 in X5. Number of leaves was found non-significant to the influence of variety at all dates of observation.

Table 2 Number of leaves per plant of maize as influenced by variety at Lamahi, Dang during spring, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance

1.1.3 Leaf area index

The experiment showed that leaf area index increased from 30 DAP to 90 DAP (Table 3). The mean LAI was found to be 0.0563 at 30 DAP and ranged from 0.0442 in X5 and 0.648 in RML 86/96. At 60 DAP, LAI was 0.810 and ranged from 0.694 in 10V10 to 0.096 in P3522. The average LAI at 90 DAP was found to be 2.959 and ranged from 2.726 in X5 to 3.327 in RML 95/96. Leaf area index wasn’t significantly different among maize hybrids at all dates of observation.

Table 3 Leaf area index of maize as influenced by variety at Lamahi, Dang during spring season, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance

1.2 Yield attributing characters

Average number of ears harvested per hectare was 60015 in the experiment. Number of ears harvested per hectare didn’t differ significantly among the maize hybrids. It ranged from 57762 in RML 86/96 to 62651 in P3522. Comparatively higher number was recorded in P3522 compared to other genotypes. Average number of kernels rows per ear was 15.76 in this experiment. It was significantly different among the maize hybrids tested. Kernel rows per cob was significantly higher in P3396 with 16.38 rows which was statistically at par with P3522 (16.24), 10V10 (16) and RML 86/96 (15.87). X5 showed significantly lower number of rows i.e. 15.03 which was statistically similar with 15.07 in RML 95/96. The mean value of number of kernels per row was found to be 36.72 in the experiment (Table 4). The number of kernels per row was found significantly different among the maize hybrids. Number of kernels per row was found significantly higher in 10V10 (41.60) which was statistically at par with P3396 (40.41) and X5 (37.79). P3522 recorded 37.03 number of kernels per row whereas RML 95/96 recorded significantly lower number of kernels per row i.e. 31.02 which was statistically similar with RML 86/96 (32.47). Average number of kernels per ear was found to be 580 in the experiment and significantly different among the maize hybrids. 10V10 produced significantly higher kernels per ear with 665.6 which was significantly at par with P3396 (661.9). RML 95/96 produced significantly lower number of kernels per ear i.e. 466.6 which was statistically similar with RML 86/96 (515.5). P3522 and X5 recorded 568.8 and 515.5 kernels per ear respectively. The value of thousand kernel weight was 308.3 g and significantly different among the maize hybrids. TKW was found significantly higher in 10V10 which had 321.3 g which was statistically similar with P3522 (317.7 g), P3396 (316 g) and X5 (310 g). There was observed significantly lower thousand kernel weight in RML 86/96 with 290.3 g which was similar with RML 95/96 (294.7 g).

Table 4 Yield and yield attributes of maize as influenced by variety at Lamahi, Dang during spring, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance

Average cob length was found to be 20.12 cm in the experiment (Table 5). Cob length was significantly influenced by the maize hybrids used. Cob length was found significantly higher in 10V10 with 22.54 cm which was statistically at par with P3396 (20.99 cm) and X5 (20.99 cm). RML 86/96 recorded significantly lower cob length of 17.37 cm which was similar with RML 95/96 (19.35 cm) and P3522 (19.48 cm). Average value of cob circumference was 15.832 cm in the experiment. It was significantly different among the maize hybrids. P3396 recorded significantly higher cob circumference of 16.567 cm which was statistically similar with 10V10 (16.24 cm) while X5 produced significantly lower cob circumference of 15.438 cm which was statistically similar with RML 95/96 (15.566 cm), RML 86/96 (15.613 cm) and P3522 (15.570 cm). The average shelling percentage was 71.19% and also significantly affected maize by hybrids grown (Table 6). It was found significantly higher in P3522 (74.61%) but statistically similar with P3396 (72.83%), 10V10 (71.73%) and X5 (70.67%). RML 95/96 recorded significantly smaller shelling percentage of 69.93% which was statistically at par with RML 86/96 (67.35%). The barrenness percentage was found to be 4.63% in the experiment and ranged from 2.92 % in 10V10 to 5.84 in P3522. Barrenness % was found non-significant to the treatments used. Average sterility percentage was found to be 10.93% ranging from 10.01% in P3522 to 12.58% in P3396. Sterility wasn’t significantly different among the hybrids used.

Table 5 Yield attributing characters of maize as influenced by variety at Lamahi, Dang during spring, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance. Ns=non-significant

Table 6 Shelling %, Sterility% and Barren% of maize as influenced by variety at Lamahi, Dang during spring, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance

1.3 Grain yield

The average grain yield of different maize hybrids was found to be 10.56 t ha^-1 (Table 7). Grain yield was found to be significantly influenced by the maize hybrid genotypes. The highest grain yield was seen in 10V10 (12.85 t ha^-1) followed by P3522 (11.65 t ha^-1), P3396 (11.59 t ha^-1) and X5 (10.62 t ha^-1) which were statistically similar. RML 86/96 and RML 95/96 recorded significantly lower yield of 8.30 t ha^-1 and 8.35 t ha^-1 respectively.

Table 7 Grain yield of maize as influenced by variety at Lamahi, Dang during spring, 2019 Note: The treatment means followed by common letters are not significantly differ from each other based on DMRT at 5 % level of significance

2 Discussion

2.1 Effect of hybrids on phenology 

Days to 90% tasseling, days to 90% silking and anthesis silking interval differed non-significantly among the maize hybrids tested (Table 3). The non-significant result in phenology might be because of the stability of heat resilient hybrids RML 95/96 and RML 86/96 during spring season. The stability of phenological behavior was found to be important criteria for developing heat resilient hybrids (Yousaf et al., 2017). Tasseling silking characteristics was found non-significant among the maize hybrids under under irrigated conditions during spring season (Jaidka et al., 2018).

2.2 Effect of variety on plant height

Plant height varied significantly during tasseling stage and at harvest (Table 4). The difference in plant height among different maize varieties might be because of genotypic variability. Genotypes were found to have significant effect on plant height of maize (Sabiel et al., 2014). 

10V10 maize hybrid showed shortest height in both tasseling stage and at harvest. Reduced plant height might help the hybrid to perform better during spring season. Lower plant height could reduce the transpiration and therefore reduce the demand for moisture during drought stress at the key growth stage (Zhang, 2016). Lower plant height during spring under heat and drought stress could help in increasing yield in maize (Su et al., 2019).

2.3 Effect of variety on LAI

Leaf area index didn’t differ significantly under the influence of variety (Table 5). The non-significantly higher leaf area of Nepali hybrids compared to commercial hybrids might be because of the adaptation of commercial hybrids to the high-density planting. Commercially developed maize hybrids have upright leaves and smaller tassels allowing more light to penetrate the leaf canopy and thus lower leaf area. Low leaf area hybrids are superior in several maize productivity traits than high leaf area hybrids. (Lambert, Mansfield, & Mumm, 2014). Leaf area index may not always be positively correlated with yield attribution.

2.4 Effect of variety on yield attributing characters and grain yield

On average, yield attributing characters viz. cob length, kernels per row, number of kernel rows per cob, thousand grain weight as well as shelling percentage were found significantly higher while number of ears harvested per hectare was numerically higher in commercial hybrids than Nepali genotypes (Table no 7, 8 and 9). Thus, grain yield was also seen significantly higher in multinational hybrids (Table no 12). Multinational commercial hybrids showed to have better performance under genotypic × environment interaction. This might be because of better genetic potential of those hybrids compared to Nepali hybrids. Across site analysis of variance revealed that highly significant effect of genotype and genotype × environment interaction (GEI) on grain yield of commercial hybrids (Tripathi, Shrestha, and Gurung, 2016).

10V10 maize hybrid showing significantly higher ear length, kernels per ear, thousand kernel weight and grain yield compared to RML 95/96 and RML 86/96 depicts positive correlation of yield attributes with yield. A strong positive genetic correlation observed among thousand kernel weight, ear weight, kernels per row, and grain yield indicates that selection for these characters can help improve maize grain yield (Malik et al.,  2005).

3 Materials and Methods

Field research was conducted at Lamahi, Dang lying on the geographical coordinates of 28˚7’0”N, 82˚18’0”E. which is 725 m above sea level. Dang climate was characterized by three seasons: winter (Nov- Feb), spring (March-May) and summer/rainy season (June-Oct). The average maximum and average minimum temperature for the cropping duration were 34.167°C and 22.67°C respectively. The average annual rainfall of Dang is 1577 mm. sample was taken before sowing of the seeds from each replication and composite sample was made and was analyzed for the initial fertility status of the soil. From soil analysis, Organic matter was found 2.02 (%), available potassium (200 kg ha^-1) were found high, total nitrogen (0.101%) was found medium while available phosphorus (35.44 kgha^-1) was found very high and soil pH was found neutral (7.1). Dang climate was characterized by three seasons: winter (Nov- Feb), spring (March-May) and summer/rainy season (June-Oct). The average maximum and average minimum temperature for the cropping duration were 34.167°C and 22.67°C respectively. The average rainfall during the growth season was 33.567 mm where maximum rainfall in February 96.9 mm. The total rainfall during the cropping period was 201.4 mm. The maximum relative humidity for the cropping period was 65% and minimum was 30%. Experiment was laid out in randomized complete block design with three replication and six treatment constituting 18 plots. The size of the individual plot was 4.2 m × 3 m (12.6 m²). Each replication was separated by 1m bund and 0.5 m width separated two individual plots. Row to row spacing was maintained at 60 cm distance with plant to plant distance being 25 cm. Number of rows in each plot was 7 with 12 seeds planted in each row.

4 Conclusions

Among the six hybrids tested, 10V10 maize hybrid produced the highest grain yield (12.5 t ha^-1) followed by P3522, P3396 and X5 with their respective yield of 11.65, 11.59 and 10.62 t ha^-1. Therefore, these hybrids are recommended for spring season in Dang valley of Nepal. The multinational hybrids performed better than Nepalese hybrids in terms of yield.

Acknowledgement

We are thankful to and Agriculture and Forestry University for the financial support and Associate Professor Santosh Marahatta for his regular guidance.

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