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Lanzhou Agro-technical Science Research and Popularization Center, Lanzhou 730000, China

1 Introduction

In Lanzhou City, the total area of cultivated land is 0.21 million ha, of which the area of mountainous dry land is 0.131 3 million ha, accounting for 63% of the total area of cultivated land. Drought is the most serious natural disaster in Lanzhou and the most important natural disaster that has a direct impact on agricultural production. To develop dry farming and to cultivate new growth points is an important measure to develop agriculture in arid areas and is needed for the increase of peasants’ income. In recent years, the production of dry farming in Lanzhou City, has made great strides. The dry farming technology of maize with film mulching technology as the center has been widely popularized and applied, and the planting area of maize accounts for 15.2% of the total planting area of crops all year round and is always more than 33 300 ha for five consecutive years[1]. The stable development of grain production has effectively promoted the increase of peasants’ income.

Under the conditions of rain-fed dry farming, the high and stable yield of maize mainly depends on the tolerance of varieties to water deficit[2], so it is very important to choose appropriate maize drought-resistant varieties to increase the yield of maize[3]. In this study, under the conditions of rain-fed dry farming, the growth period, yield and population characteristics of different maize varieties were compared to select suitable high-yield maize varieties for dry farming areas.

2 Materials and methods

2.1GeneralsituationofthetestareaMengjiashan Village is located in the arid mountainous area of southeastern Yuzhong, with the average elevation of 2 400 m, the annual average temperature of 7.4℃, the annual average precipitation of 350 mm, the annual evaporation of 1 450 mm, the annual frost-free period of 150 d, and the annual sunshine duration of 2 500 h. Here precipitation from July to September accounts for 56% of annual precipitation. In 2016, high temperature in April appeared earlier than that in the same period in an average year; from July to September, average temperature was about 1.3℃ higher, and precipitation was over 20% less than that in the same period in an average year. In this year, precipitation is small, and drought lasts for a long time. The experimental area is a typical semi-dry loess hilly region, and the test soil is loessal soil.

2.2TestvarietiesThere were 12 maize varieties in the experiment, including Xianyu 335, Baodan 3, Lianda 169, Jindan 73, Ganyu 804, Ganyu 812, Ganyu 816, Ganyu 810, Ganyu 803, Ganyu 811, and Dunyu 16. Local cultivar Jinsui 4 was as the control.

2.3TestmethodsRandomized block arrangement was adopted, and there were three repetitions. The area of each plot was 35.2 m2(8.0 m×4.4 m). Seeds of the maize varieties were sown in trenches on two ridges and were covered by plastic mulch. Before the seeds were sown, farmyard manure (45 000 kg/ha), urea (150 kg/ha) and ordinary superphosphate (750 kg/ha) were applied, and the planting density was 49 500 plants/ha. Soil preparation and mulching were conducted on November 1, 2015, and sowing was carried out on April 9, 2016. At the jointing stage, urea (300 kg/ha) was applied again. Other management measures were taken like fields. The growth period of maize was recorded. In the mature period, 10 maize plants were collected from each plot to calculate yield.

3 Results and analysis

3.1GrowthperiodSeen from Table 1, all maize varieties sprouted 30-35 d after sowing. The growth period of the maize varieties was 115-135 d. Among these maize varieties, the growth period of Ganyu series of maize varieties was between 115 and 119 d, and these maize varieties became mature early due to drought. The growth period of Xianyu 335, Lianda 169 and Dunyu 16 was more than 130 d, so they are medium and late maturing varieties, and their growth period was 8 d longer than that of Jinsui 4 at least.

Table1Comparisonofgrowthperiodofmaizevarieties

VarietySowingdateSeedingdateBelldateTasselingdateMaturationdateGrowthperiod∥dXianyu33504-0905-1006-2507-1009-23135Baodan304-0905-1205-2507-1009-15125Lianda16904-0905-1407-0707-1809-25137Jindan7304-0905-1006-2207-1009-12125Ganyu80404-0905-1306-2207-0509-06115Ganyu81204-0905-0906-2207-0509-04117Ganyu81604-0905-0906-2207-0509-04119Ganyu81004-0905-0906-2207-0509-04117Ganyu80304-0905-0906-2207-0509-04117Ganyu81104-0905-0906-2207-0509-06119Jinsui4(CK)04-0905-1006-2807-1009-15127Dunyu1604-0905-1207-1207-2209-25135

3.2MaincharactersAccording to Table 2, the plant height of these maize varieties was between 1.71 and 2.23 m, of which Xianyu 335 was the highest (2.23 m), 0.09 m higher than Jinsui 4. The plant height of early maturing varieties such as Ganyu 816, Ganyu 810, Ganyu 803 and Ganyu 811 was smaller than 1.90 m, and they were shorter than CK. The ear position height of these maize varieties ranged from 47.33 to 98.87 cm, of which Dunyu 16 had the maximum ear position height, followed by Jinsui 4, while Lianda 169 had the minimum ear position height. Among these maize varieties, the row number per ear of Lianda 169 was the largest, followed by Xianyu 335, and the the row number per ear of Jinsui 4 was 16. Lianda 169 had the largest grain number per row, followed by Dunyu 16. The grain number per row of Ganyu series was between 34 and 40, 4-8 smaller than Jinsui 4. The ear diameter of Xianyu 335, Lianda 169, Jinsui 4, and Dunyu 16 was larger than 4 cm, of which Xianyu 335 had the largest ear diameter. The ears of Jinsui 4 was the longest, followed by Dunyu 16. In a word, the ear diameter, ear length, row number per ear, and grain number per row of Ganyu series were relatively small, while these characters of Xianyu 335, Lianda 169, Jinsui 4, and Dunyu 16 were relatively large.

Table2Maincharactersofthemaizevarieties

VarietyPlantheight∥mEarpositionheight∥cmRownumberperearGrainnumberperrowEardiameter∥cmEarlength∥cmXianyu3352．2369．7517．039．04．6518．38Baodan31．7147．3313．638．43．5418．88Lianda1692．0249．6018．044．84．2919．48Jindan731．9156．6015．039．53．4519．18Ganyu8042．1375．3316．038．03．8818．50Ganyu8122．0174．3313．840．43．6518．54Ganyu8161．8858．8412．437．23．5416．76Ganyu8101．7958．4614．834．23．5217．72Ganyu8031．7872．3113．633．23．2216．81Ganyu8111．7666．3413．834．63．4217．15Jinsui4(CK)2．1485．2316．043．34．2722．67Dunyu162．2198．8716．844．24．3120．14

3.3YieldandyieldcompositionThe grain weight per ear of the maize varieties was 100.23-218.56 g, of which Dunyu 16 had the largest grain weight per ear (218.56 g), 15.52 g larger than Jinsui 4 (Table 3). The cob weight of Jinsui 4 was the highest, up to 45.76 g, while the minimum of cob weight was only 20.14 g. The hundred-grain weight of the maize varieties was between 23.24 and 34.22 g, and the hundred-grain weight of Dunyu 16 was 34.22 g, 2.64% higher than that of Jinsui 4. The double ear rate of Lianda 169 was the highest, reaching 60%, followed by Jindan 73. Each plant of Xianyu 335, Jinsui 4, Dunyu 16, Ganyu 812, Ganyu 816 and Ganyu 803 had only an ear. The yield of the maize varieties was between 3 036.37 and 8 080.93 kg/ha, of which the yield of Lianda 169 was the highest, followed by Dunyu 16, 31.40% and 7.64% higher than that of Jinsui 4 respectively. The yield of other maize varieties was lower than that of Jinsui 4, of which Ganyu 803 had the lowest yield. The yield of Lianda 169 and Dunyu 16 was high, so they could be popularized, while Xianyu 335 and Jindan 73 need to be studied through an experiment.

Table3Yieldandyieldcompositionofthemaizevarieties

VarietyGrainweightperear∥gCobweight∥gHundred?grainweight∥gDoubleearrate∥%Yieldkg/haChangingrateofyield∥%OrderXianyu335160．1533．1426．9904851．58c-21．125Baodan3139．9127．7227．73104662．28c-24．207Lianda169187．3534．6425．47608080．93a31．401Jindan73160．1522．5623．65205821．90bc-5．354Ganyu804142．2527．7926．20104740．25c-22．936Ganyu812120．7520．2926．1103658．00d-40．5310Ganyu816113．8721．4026．8203449．58d-43．9211Ganyu810122．1223．1623．2403699．50d-39．859Ganyu803100．2320．1424．1203036．37e-50．6412Ganyu811121．3221．3423．4653859．03d-37．268Jinsui4(CK)203．0445．7633．3406150．89b0．003Dunyu16218．5644．3834．2206621．06b7．642

4 Conclusions

The growth period, characters and yield of the 12 maize varieties were analyzed. The results showed that the growth period of the maize varieties was 115-137 d. The yield of Lianda 169 and Dunyu 16 was 31.40% and 7.64% higher than that of Jinsui 4 respectively. Their plant height and ear position were appropriate, and their grain number per ear was large, while their hundred-grain weight was large, so they could be popularized and planted in dry farming areas of Lanzhou City. The yield of Ganyu series as early maturing varieties was low, so they should not be popularized. Xianyu 335 and Jindan 73 need to be studied through an experiment.

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