Determination of Arid and Temperature Resistant Sweet Corn (Zea mays saccharata Sturt) Lines
Abstract
The objective of the present study is to identify aridity and temperature resistant sweet corn variety candidates and to provide resource material for development of new hybrid varieties. The research was designed as three -peat random blocks experimental design in Siirt and Sakarya locations in 2014, and irrigation application was conducted with drip irrigation method. Mean plant water consumption in control (I100) was 808 mm and 633 mm in Siirt and Sakarya, and the mean irrigation water amount was 684 mm and 138 mm, respectively. The statistical significances of differences among soil moisture content, chlorophyll -meter value, crop water stress index, fresh corncob, and grain yield were investigated. The arid and temperature resistant sweet corn line was determined according to soil moisture content, chlorophyll -meter value, and crop water stress index. The most arid and temperature resistant corn line, variety line #2, had the lowest moisture content and crop water stress index value but the highest chlorophyll -meter value. We found that to determine the arid and temperature resistant corn lines, soi l moisture content values can also be used together with chlorophyll -meter values and crop water stress index.
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Introduction
Sweet corn is one of the horticultural crops and fresh ears have consumed the most. Fresh ear yield or dry grain yield are considered as yield components of such a crop (Hirich et et al., 2014).It has yellow, white and bicolored ear types. Cultivars are classified as early, mid, and late season, depending on their maturity days and late season cultivars in general are the highest quality (Lerner & Dana,1998).Corn yield and quality are mainly affected by environmental, cultural and genetic factors of cultivars (Carpıcı et al., 2010).In an area where there is no water shortage, full irrigation results in maximum production. In regions with limited water supply, deficit irrigation could be very beneficial to improve water use efficiency and irrigated lands with same amount water. In addition, deficit irrigation technique may increase the net income of farmers by increasing the crop production per unit water applied (Galavi & Moghaddam 2012) and is now studied world wide as one of the practices to save water (Periera et et al., 2002). Even Hirich et al. (2014) reported that with regards to yield and saving water, 75% of full irrigation was optimal treatment for sweet corn crop. Under deficit irrigation, crop production per unit area is less than the maximum yield per unit area, but net profit is higher (Mohammadpour et al. 2013).
In that context, the importance of the studies that aim to develop new varieties, tolerant to drought and heat is becoming more important. Although Turkey has suitable ecological regions to grow sweet corn, so far no comprehensive studies indicating which sweet corm varieties are high efficiency were performed under drought stress conditions.
Since sweet corn is a summer plant, heat and aridity that occur during the growth season are among the most important abiotic stresses that limit the sweet corn production. Based on different years, these negative stress conditions could cause significant loss in sweet corn yield. This fact makes it necessary to determine the resistance of sweet corn varieties and variety candidates that are resistant to aridity and could adapt to different ecological regions in Turkey. Thus, a need for a study such as the present one, which would determine aridity resistant sweet corn variety candidates and obtain heat and aridity resistant genotypes, has arisen. The objective of the study is to identify aridity and temperature resistant sweet corn variety candidates and to provide resource material for development of new hybrid varieties. For this purpose, the resistance of sweet corn variety candidates and genotypes against aridity stress, their soil moisture and chlorophyll content during the growth season, and their crop water stress index (CWSI) values were monitored and identified. The variety candidate with the lowest soil moisture content, CWSI value, and that utilized the irrigation water with optimum efficiency was considered as the most resilient against aridity stress.
The other main goal of the study is to analyze yield, irrigation water requirements, crop water consumption comparatively of our original sweet corn lines for Siirt and Sakarya provinces of Turkey.
Conclusion
In general, deficit irrigation affected the growth and yield of sweet corn. Variety candidate no. 2 had the highest crop water consumption level under no irrigation condition with an average yield value of 7746 kg ha-1. Therefore, sweet corn variety candidate no.2 which has an economic efficiency of crop water use, could a vail even the slightest moisture in soil, has a low crop water consumption, and has an optimum level of grain yield by comparison to others, and has the lowest CWSI as 0.14, and it has been determined to be resistant against hot and semi -arid climate conditions. Thus, it was determined as a result of the findings of the study that with the use of no: 2 variety candidate as a parent (No.2), which was resistant to aridity and temperature stress, utilized the irrigation water with optimum efficiency, and with high chlorophyll content, an increase in yield could be attained. We found that to determine the arid and temperature resistant corn lines, soil moisture content values can also be used together with chlorophyll -meter values and crop water stress index.
