Seasonal Yield Response Factor for Red Bombay Onion (Allium cepa L.) Variety in Arba Minch, Ethiopia

Background: For better water resources management in the areas of water shortage for crop production, deficit irrigation is very important. The understanding of the yield response factor to water deficit is crucial for efficient irrigation water management. Deficit irrigation for studying yield response factors is always practiced in the way of stressing the demand of the crops. The present study was done for the determination of the seasonal yield response factor of red Bombay onion variety under Arba Minch agro climate condition. Furthermore, it also examined the effect of furrow irrigation systems on the seasonal yield response factor. Methods: The experiment was conducted from August to November 2019. The experiment had six treatments, which were the combination of two furrow irrigation systems and three irrigation levels. Data were collected for soil moisture before and after each irrigation and bulb yield. The seasonal yield response factors were determined through simple linear regressions using SPSS software. Result: When considering the furrow irrigation system as a factor, the seasonal yield response factor for alternate furrow irrigation system was 1.18 while for paired row furrow irrigation system was 1.07. This red Bombay variety of onion clearly shows more sensitive to water stress for alternative furrow irrigation systems than paired row furrow irrigation systems. Therefore, in the area of water shortage paired row furrow irrigation system is better than alternate furrow irrigation system. The seasonal yield response factor as a wall for red Bombay onion variety in Arba Minch agro-ecological condition was 1.12. Therefore, the red Bombay onion variety in Arba Minch agroclimate condition was sensitive to water stress.

Alleviating the adverse effects of deficit irrigation in Flame seedless grapevine via Paulsen interstock

Using interstock with a potential genetic base is considered more recent and sustainable strategy for mitigating the water deficit. This investigation was carried out on transplant of Flame seedless (Vitis vinifera) grapevine grafted onto two rootstocks namely; Freedom (Vitis champinii x 1613C) and 1103Paulsen (vitis berlandieri x Vitis rupestris) with or without 1103Paulsen as interstock to determine its performance under deficit irrigation condition (50% of field capacity). The results indicated that Paulsen as rootstock or as interstock significantly increased the growth vigor of Flame seedless scion as well as the leaf content of total proline, phenols and sugars. Paulsen rootstock has decreased stomatal conductance, leaf transpiration rate and increased diffusion resistance under 50% deficit irrigation compared with grafting on Freedom rootstock. Moreover, Paulsen as interstock for Flame seedless grafted onto Freedom rootstock significantly increased relative water content accompanied by an increase in thickness of leaf anatomical characters such as midvein, lamina, palisade, xylem and phloem tissue under deficit irrigation compared with grafts without Paulsen interstock. This study suggests that using Paulsen as interstock, can be an adaptation strategy for water stress through controlling in some morphological, chemical physiological and anatomical responses of scion.

Evaluation of chemical composition of roots of three sugar beets varieties growing under different water deficit and harvesting dates in Upper Egypt

Field experiments were carried out at Shandaweel Agricultural Research Station, Sohag, Egypt to study the effects of deficit irrigation and harvesting date chemical composition of three sugar beet varieties. A split block design with three replications was used. Main blokes were assigned to three irrigation water regimes (100%, 85%, and 70% of water requirement). The sub blot was occupied by three harvesting dates (180, 195 and 210 days). Sub- sub plots comprised three sugar beet varieties namely (RAVEL, SV1841and SA1686). Results indicated that reducing water supply reduced alpha - amino N present in the second season, Na present in the second season, and K present and sugar lost to molasses, but increased sucrose present, extractable present, QZ present, purity present, extractability present. Increasing harvesting date increased K present, sucrose present, extractable present, QZ present, purity present, extractability present but reduced alpha - amino N present, Na present and sugar lost to molasses in the second season. Sucrose present, extractable present, QZ present purity present and extractability present of RAVEL and SA1686 varieties were almost comparable but higher than those of SV1841 variety.