Bassiouni A. Zayed

The present investigation was conducted under normal and salinity conditions during the two rice successive seasons of 2020 and 2021. Three CMS lines of rice, IR69625A, G46A and GAB-A were used as female parents. In addition, four Egyptian tester lines viz., Giza179, PR5, PR6 and GZ9399 were used as testers beside their twelve F1 crosses. A randomized complete block design with three replications was used and the data were analyzed according to line × tester design. The results indicated highly significant differences among genotypes, parents, crosses and parents vs. crosses under the two environments (normal and salinity conditions).The results showed that dominance genetic variance (σ²D) was greater than additive genetic variance for Plant height, Number of panicles/plant, Spikelet fertility %, 1000-grain weight, Grain yield/plant, sodium content and potassium content under normal and salinity conditions, Panicle weight under salinity condition, indicating that non-additive gene action played an important role in the inheritance of this trait. For heterosis over the mid-parents (H.M.P.%): The most desirable hybrids; For grain yield plant-1, the highly values and highly significant heterosis based on mid-parents for grain yield plant-1 were observed for the crosses GAB-A/PR5, GAB-A/PR6, GAB-A/GZ9399, G46A/GZ9399, G46A/PR6 and G46A/PR6 under both conditions. The following genotypes could use in breeding program and expected improvement in such traits under normal and saline condition, G46A, PR6, GZ9399, Giza179 and GAB-A as a good donor. G46A/PR6, G46A/PR5, GAB-A/ PR6 and IR69625A/Giza179 could use as good crosses.

The study was carried out in of 2015 and 2016 seasons at the Experimental Farm of El-Sirw Agriculture Research Station, Damietta Governorate, and Egypt. The main objective of an attempt was to determine the effect of short, medium and prolong irrigation intervals (irrigation every three, six and nine days) and gypsum rates (0, 0.5,1.0 and 1.5 t ha-1 CaSO4) on some soil prosperities, some plant elements, plant growth and grain yield of Sakha 104 rice cultivar, under saline soil conditions. A strip plot design, with four replicates, was used. The horizontal plots were devoted to irrigation intervals, however, the gypsum rates were allocated in the vertical plots. The soil of the experimental site was clayey and salinity levels were 7.5 and 7.3 dSm-1 in 2015 and 2016 seasons, respectively. The results obtained could be summarized as follows: Irrigation every three days increased chlorophyll content, LAI, plant height, number of tillers, panicle length, number of panicles, filled grains/panicle, panicle weight, 1000-grain weight, grain and straw yields as a compared with irrigation every nine days, which recorded the highest values of unfilled grains. Irrigation every three days significantly increased soil bulk density as well as Ca++ and K+ (in the soil and plant). However, it decreased the soil EC, Na+ (in the soil and plant) and Na/K ratio in the plant. Irrigation every three days consumed the highest amount of irrigation water, while prolonged irrigation intervals up to six and nine days tended to decrease the amount of water used. Furthermore, nine days treatment recorded the highest water use efficiency. Gypsum (as a soil amendment) rated 1.5 t1 CaSo4 ha- significantly raised all studied growth parameter (except plant height), grain yield and its components without any significant differences with 1.0 t ha-1 CaSo4 in some traits in both seasons. Gypsum at the rate of 1.5 t ha-1 CaSo4 mitigate the hazardous effect of salinity by decrease soil EC, Na+ (in the soil and plant) and Na/K ratio in the plant. Generally, under the same condition, irrigation every three days and gypsum at the rate of 1.5 t ha-1 CaSo4 are favorable for improve soil properties and enhance rice productivity under saline soil conditions.

Water scarcity and soil salinity are the main constrains for rice production in Egypt. Rice is the greatest consumer of water among all crops. A system of growing rice on raised beds or levees and system of rice intensification (intermittent irrigation system) where water is applied only in the furrows between beds, is hypothesized to reduce water input for rice. For water saving with considerable rice grain yield under newly reclaimed saline soil, two field experiments were conducted to innovate new rice planting technology at the experimental farm of El Sirw agriculture research station during two successive seasons of, 2011 and 2012. The system of rice cultivation technology were traditional transplanted with watering every four days as traditional methods (control treatment) up to 6 cm water depth, system of rice intensification (SRI) with intermittent irrigation system, dry rice seed on dry levees with watering as upland crop up to 30 days after sowing then shifting watering every four days up to 1 cm water depth and transplanted rice on levees with watering every four days up to 1 cm water depth. The used variety in this experiment was Giza 178 (drought and salt tolerant Egyptian rice variety). The soil was clayey in texture with salinity level of 6.5& 6.0 dS/m in 2011 and 2012 seasons, respectively. The obtained findings revealed that the different systems of rice planting and technology significantly showed variation in their impact on soil properties, yield and yield attributing characteristics of rice as well as saved water and water productivity in rice crop under such circumstances. SRI had the lowest values of soil EC, soluble cations and anions as well as bulk density in both seasons. Furthermore, SRI gave the highest values of yield and most of yield components as well as chlorophyll content in the leaf at heading without any significant differences with those obtained by Traditional transplanted one. The dry seed on dry levees gave the highest values of soil EC, soluble and anions as well as bulk density and, lowest value of pH in both seasons followed by transplanted on levees but less than the initial values of them. the system of dry seed on dry levees gave the lowest values of total applied water (8899.0 &8910.0 m3 / ha) in the first and second seasons, respectively followed by transplanted rice on levees and then SRI in both seasons. In addition, dry seed on dry levees had the highest values of water use efficiency and water saved (0.87 and 0.91 as well as 4290) for WUE, water saved in 2011 and 2012 seasons, respectively, followed by rice transplanted on levees and then SRI(Table9). Traditional rice transplanting of flat soil gave the highest values of total applied water (13618 &13629 m3 /ha) and the lowest values of water use efficiency (0.61 and 0.64) in the first and second seasons, respectively. Considering soil, yield and water saved , the SRI superior the rest of current investigated system of rice cultivation under present conditions.

Salinity is the main constrain to rice production in Egypt. The high heterosis displayed by hybrid rice might be exploited for the enhancement of rice productivity in the presence of economically-important stresses such as drought and salinity. Three field experiments were conducted during summer seasons of 2010, 2011 and 2012 rice seasons at El- Sirw Agricultural Research Station as saline soil and EL- Gemmiza Agricultural Research Station as normal soil. The salinity levels were 8.2, 8.5 and 8.3 dsm-1 in ,2010, 2011 and 2012 seasons, respectively as saline soil and 1.9 and 1.8 dsm-1 for normal soil. In 2012 season, the best selected genotypes compared with the salt tolerant variety Giza 178 were physiologically evaluated under saline soil. Fifteen rice genotypes, nine hybrids, SK2034H, SK2046H, SK2035H, SK2058H, SK2074H,SK2010H, SK2121H, SK2122H, SK2037H, and six inbreeds rice, Giza 177 (salt sensitive), Giza 178 ( the best salt Egyptian variety), Giza 182 (Sensitive one), Sakha 101 (moderate salt tolerant one), Sakha 102 ( Sensitive one) and Sakha 104 ( moderate salt one) were used in this investigation . Studied genotypes significantly varied in all studied parameters under both saline and normal soils. Under normal soil all tested hybrids significantly surpassed the studied inbreeds but hybrid 8 was less all of inbreeds except Giza 177 and Sakha 102. While, under saline soil conditions, there are only three hybrids; SK2034H, SK2035H and SK2058H markedly exceeded the salt tolerant inbred rice variety Giza178 in large score. The hybrid SK2046H gave the highest number of panicle hill-1 under normal condition, while, SK2058H gave the highest values of panicle number under saline soil for this trait.The ability of SK2034H, SK2055H, SK2058H, Hybrids and Giza 178 to keep high filled grains under saline soil The results obtained indicated that the three hybrids SK2034H, SK2035H and SK2058H could be recommended to be grown under saline soil with yield increase of 16–22 % over Giza178 as inbred salt tolerant one that may be due to their high heterosis. On the other hand, SK2058H markedly surpassed the other two hybrids. It could be concluded that SK2058H gave the highest means in all seedling characteristics, number of white roots, root dry weight of seedling, shoot dry weight, root length, shoot length and number of leaves plant-1 under saline soil during the last seasons without significant differences compared with those produced by hybrid SK2034H. On the other hand, the lowest values of aforementioned traits were recorded by Giza 178 inbred salt tolerant variety.

The high heterosis displayed by hybrid rice might be exploitable for the enhancement of rice productivity in the presence of economically-important stresses such as drought and salinity. The current study aimed to find out the possibility of exploring hybrid rice under drought and salinity stresses. Rice varieties, Giza 177 and Giza 178 (inbred rice varieties) and SK2034H (the first hybrid rice released in Egypt) were tested under normal, saline and drought conditions using a split plot design with four replications. The investigation conducted under a controlled system in the greenhouse and field(Farm) of Rice Research and TrainingCenter, Sakha, Kafr EL-Sheikh as well as at El-Sirw Agriculture Research Station i.e. saline soils, Egypt during two growing seasons of 2010 and 2011 in greenhouse and in 2011 under field conditions. The three rice varieties varied significantly in all estimated parameters and in their stress tolerance. The hybrid variety SK2034H was more tolerant to salinity and drought than Giza 178, the most tolerant Egyptian inbred rice varieties. This high capability of the Egyptian-developed hybrid might be mainly attributed to its greater root vigor, leaf area, flag leaf area, chlorophyll content, dry matter production, filled grains number, panicle number and weight; and lower sterility percent (sterility%). Furthermore, SK2034H had higher Na+ and K+ content than Giza 178, leading to a resulting in improved tolerance to stress. On the other hand, Giza 177 was more stress sensitive, possibly due to weakness of root system, poor growth, chlorophyll degradation, high Na/K ratio, and high sterility both stresses. The result obtained from saline soil and drought tested under field conditions came to confirm the obtained one under green house. Interestingly, both SK2034H and Giza 178 were at the same level for salinity tolerance, while SK2034H was more drought tolerant than Giza 178. stress. From the aforementioned results, SK2034H could be used on large scale especially under salt affected areas and in the end tail of irrigation canal.

For optimizing rice grain yield under saline conditions; the current trail has been performed during 2009 and 2010 seasons at El-Sirw Agriculture Research Station, Damietta province, Egypt. The main objective of this attempt is to find out the response of six different rice varieties namely, Sakha101, Sakha102, Sakha104, Giza177, Giza 178 and Egyptian hybrid one (Sk2034H) to various phosphorous rates i.e. 0, 30, 60 and 90 kg P2O5 ha-1 under newly reclaimed saline soil. The experiments were performed in a split plot design with four replications where, rice varieties were arranged in the main plots and phosphorous rates were occupied the sub plots. The salinity levels of the experimental site were 8.0 and 7.50 dSm-1in 2009 and 2010 seasons, respectively with clay soil texture. Growth parameters, nitrogen and phosphorous leaf contents at heading as well as grain yield and yield attributing characteristics were measured at harvest. The obtained results could be summarized as following, the tested rice varieties were significantly differed in their salt tolerance and in their response to phosphorous rates under saline conditions. Giza 178 and SK2034H hybrid one were the most salt tolerant varieties. Phosphorous application significantly improved rice growth parameters (dry matter, LAI and chlorophyll content). Nitrogen and phosphorous leaf content were significantly increased by increasing phosphorous rates up to 90 kg P2O5 ha-1. Phosphorous application was found to be effective in enhancing rice grain yield and all yield attributing characteristics. Grain yield respond to P application up to 90 kg P2O5 ha-1, while most of yield component up to 60 kg P2O5 ha-1 Interestingly, the high yielding rice varieties in the terms of Giza 178 and Sk2034H significantly responded to application of phosphorous up to 90 kg P2O5 ha-1. In addition, the rest rice varieties were significantly responded to phosphorous application up to 60 kg P2O5 ha-1. So, in case of newly reclaimed saline soil conditions, it could be recommended to grow Giza 178 and Egyptian hybrid one rice varieties under the same conditions with adding 90 kg P2O5 ha-1

To exp < /strong>lore hybrid rice cultivation under Egyptian saline soils using its hybrid vigor in salinity tolerance, two field experiments were conducted under saline soil during 2005 and 2006 seasons at Research Farm of El Sirw Agriculture Research Station. Enhancing seedling vigor and salinity tolerance of hybrid rice as well as its grain yield were the main approaches during the set up of this experiment. The type of experimental soil was clayey with salinity levels of 7.5 and 7.35 dS/m in 2005 and 2006 seasons, respectively. For above mentioned purposes, the seeds of Egyptian SK2034H rice hybrid (Egyptian Hybrid 1) were soaked in 1-water (as a control treatment), 2- ZnSo4(2%) , 3- diammounum phosphate (DAP)(2%), 4- NaCl(1%) ,5-GA3 (120 mg/l), 6-cytokinine (75 mg/l) and 7- Salicylic Acid (80mg /L). The seedling vigor of SK2034H hybrid rice was measured at 30 days after sowing whereas, root and shoot traits as well as leaves and root chemical contents were estimated. Furthermore, growth and grain yield and its components were estimated. The obtained results showed that pre-sowing seed treatments were found to be significantly effective in enhancing seedling vigor of SK2034H and improved its growth and its favorable nutrient content such as N, P and K. Therefore, the salinity withstanding of hybrid rice was raised which resulted in proper growth and reasonable grain yield and its components under salt stress. The most effective treatments were GA3, NaCl and Salicylic Acid. These treatments clearly demonstrated their desirable effect on seedling vigor, growth parameters and grain yield of hybrid rice under salt stress. Moreover, the all studied traits were significantly affected by the current treatments involving seedling vigor traits, rice growth traits at heading and grain yield and its components.