عنوان مقاله [English]
In arid and semi-arid regions, efficient use of water through improved cultivars with less water requirement and more drought tolerance is a basic important way to achieve assurance and stability of crop production. Water use efficiency (WUE) indicates the amount of consumed water for yield production and is defined as the ratio of dry matter or economic yield weight (g) to used water weight (m3). Indigo varieties are grown in many countries as ornamental plants for indigo color production and also as medicinal vegetative plants. Indigo (Indigofera tinctoria L.) is a valuable species of legumes that it's cultivation have an old background in Jiroft, Kahnooj, Bam and Iranshahr. It is known as a drought tolerant plant but in seedling stage, it is sensitive to water stress and requires sufficient water for seed production in flowering time. The aim of this experiment is evaluation of leaf and grain yield and WUE in existent and prevalent indigo ecotypes in Kerman south region in order to select the best ecotype for planting in this region in future.
Material and Methods
This experiment was conducted during two years in Jiroft, Kerman, as split plot based on a randomized complete block design with three replications. Different irrigation levels (50, 75 and 100% of water requirements) and four ecotypes (Jiroft, Kahnooj, Rigan and Ghaleh-Gange) were considered as the main and sub plots, respectively. The leaf dry weight, seed yield, water use efficiency base on leaf and seed were measured.
Results and Discussion
The results of ANOVA indicated that drought stress has significant effect on all of the measured traits. In addition the effect of drought × year was considerable on seed yield and seed WUE, while it was not on leaf yield and leaf WUE. The most seed yield obtained in normal condition in second year and the most seed WUE was reported in same year in average drought stress. For all of traits, the highest means obtained from normal conditions except for leaf WUE, which was obtained from severe stress conditions. Ecotype effect was remarkable for all of traits. Ecotype×year and ecotype×drought effects were significant for leaf WUE. Ecotype×drought was significant about seed yield too. For ecotype×year effect, highest leaf WUE was related to Jiroft ecotype in second year and for ecotype×drought effect the highest means of leaf WUE and seed yield were related to Jiroft in severe drought stress conditions and normal conditions, respectively. However, the results of this research showed that Jiroft and Roudbar ecotypes had higher leaf dry weight (5100.9 kg.ha-1), seed yield (331.75 kg.ha-1) and water use efficiency of leaf (1.24 kg.m-3) compared to other ecotypes under severe water stress conditions.
The results of this experiment indicated that drought stress notably influences leaf and seed yield in indigo. With consideration of drought × ecotype effect, in severe drought conditions Jiroft and south Roodbar ecotypes had no significant difference and these two ecotypes had the highest means for all of traits. Management of production conditions in order to leaf yield improvement is necessary since the aim of indigo cultivation is leaf production and color industry. In this way, as warm and drought climate conditions in sought of Kerman and necessity of cultivation pattern change in order to water economize and increase economic value, cultivation of these two ecotypes is recommended in alternation after wheat and vine crops.