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SCREENING for stable genotype entails estimating the genotype (G)×environment (E) interaction (GEI) in multi-environmental trials (MET). Quinoa is a nutritionally rich crop as a source of vitamins, minerals and essential amino acids. It has been introduced to many countries in diverse regions worldwide. We evaluated five genotypes of quinoa under ten environments including irrigated and rain-fed conditions across Egypt. We used several stability parameters as well as additive main effects and multiplicative interaction (AMMI) analysis to determine the best genotype for each environment/location across Egypt. Based on AMMI analysis of variance, the sum of squares (SS) of E, G, and GEI explained ≈ 78%, 14%, 8%, respectively, of the treatment sum of squares. The SS of interaction principal components analysis axis1 (IPCA1) and IPCA2 explained 75 and 18%, respectively. KVL-SRA3 was the most stable genotype according to ecovalence value (Wi), to deviation from regression coefficient value (S2di) of Eberhart and Russell and to IPCA1, IPCA2 and AMMI stability value (ASV). Regalona was the most unstable genotype based on the same parameters. These results were visualized using AMMI biplot analysis, which revealed that KVL-SRA3 was widely adapted to all environments unlike Regalona that was poorly adapted to most environments. The Spearman’s rank correlation among different stability parameters was significantly variable for both the five-quinoa genotypes and the ten investigated environments. Our results indicated that most stability parameters were consistent with AMMI parameters in identifying stable genotypes with some exceptions according to the concept of each of stability parameter (agronomic or biological). This study is an important step to open doors for the adoption of an extraordinary nutritional crop in Egypt.

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Due to the environmental changes, especially global warming, water scarcity will be more serious in the water shortage areas. Efficient and judicious husbandry of the limited water resources is very important. Usually irrigation water is applied considering only the plant water need whereas the impact of the excess water on the soil air O2 is ignored. Applied water fills the soil pores, replaces the soil air and reduces the amount of soil air O2. Lack of or insufficient soil air O2 reduce root growth, nutrients availability and photosynthesis rate, result in sever reduction in crop yield. The study was conducted in a greenhouse at the Okinawa Subtropical Station, JIRCAS. Five wooden boxes (180cmX90cmX30cm) were connected with each other. Six galvanized batteries along with a T-type thermocouple, was set at the entrance of the first box and at the end of the each box. Nine tomato (var. First Power) seedlings were transplanted in each box on February 18, 2005, and grown as a normal crop. At the flowering stage, soil surface in the boxes was covered by white polyethylene sheets and closed tightly to stop entry of air into the soil through the soil surface. Tomato was irrigated as and when required with a PVC pipe inserted in the surface of the boxes. We successfully developed a soil air O2 creation technique connecting wooden boxes with each other and in situ soil air O2 measurement using the galvanized battery. The results revealed that the amount of soil air O2 gradually reduced from the first box to the last one. The available soil air O2 concentration in the first box was 20.1% while it was 12.8 % in the last box. Due to the reduction in soil air O2, chlorophyll content and root dry matter were drastically reduced causing reduction of tomato yield from 2 to 18%. The tomato yield was 28.5 ton/ha in the first box, while 23.4 ton/ha in the last box. The seasonal mean soil air O2 indicated that by decreasing the available soil air O2 content by 1%, the tomato yield would reduce by 0.88 t/ha. Therefore, consideration of the balance between soil air O2 and soil water while deciding amount of irrigation water may increase crop yield, water savings and water use efficiency.