Rice production under salinity stress is a critical challenge facing many countries, particularly those in arid and semi-arid regions. This challenge could be handled by applying novel approaches to overcome yield limiting factors and improve resource use efficiency. The usage of nanoparticles (NPs) could be a beneficial approach to managing the growing problem of soil salinity. The aim of our study was to investigate the advantageous effects of soaking and foliar application of silicon (Si) and selenium (Se), (NPs-Si at 12.5 mg L⁻¹ and NPs-Se at 6.25 mg L⁻¹) on root characteristics, moropho-physiological traits, and yields of two rice varieties (i.e., Giza 177 as a salt sensitive and Giza 178 as a salt tolerant) grown in saline soil compared to untreated plants (control treatment). Results showed that soaking NPs-Se resulted in the highest value of root thickness for Giza 178 (0.90 mm, 0.95 mm) and root volume (153.30 cm³, 154.30 cm³), while Giza 177 recorded 0.83 mm, 0.81 mm for root thickness and 143.30 cm³, 141.30 cm³ for root volume in the 2018 and 2019 seasons, respectively. Soaking NPs-Se, NPs-Si and foliar application of NPs-Se at BT resulted in the highest relative water content and dry matter, while foliar application of NPs-Si at BT gave the highest leaf area index of rice plants compared to the other treatments. Giza 178 (i.e., salt tolerant variety) significantly surpassed Giza 177 (i.e., salt sensitive variety) in the main yield components such as panicle number and filled grains/ panicle, while Giza 177 significantly exceeded Giza 178 in the panicle weight, 1000-grain weight, and unfilled grains number/ panicle. Soaking NPs-Se and foliar application of NPs-Si at BT resulted in the highest grain yield of 5.41 and 5.34 t ha⁻¹ during 2018 and 5.00 and 4.91 t ha⁻¹ during 2019, respectively. The salt sensitive variety (Giza 177) had the highest Na⁺ leaf content and Na⁺/K⁺ ratio as well as the lowest K+ leaf content during both seasons. Applying nano nutrients such as NPs-Si and NPs-Se improved the yield components of the salt sensitive variety (Giza 177) by enhancing its ion selectivity. Both NPs-Si and NPs-Se had almost the same mode of action to mitigate the harmful salinity and enhance plant growth, and subsequently improved the grain yield. In summary, the application of NPs-Si and NPs-Se is recommended as a result of their positive influence on rice growth and yield as well as minimizing the negative effects of salt stress.

A field experiment was carried out at El-Sirw Agriculture Research Farm at Damietta governorate, Egypt in 2018 and 2019 seasons. This investigation aimed to be study the effect of foliar application of three silicon sources at three rates for each, i.e. nano silica at 50, 100 and 150 ppm and potassium silicate as well as magnesium silicate at 500, 1000 and 1500 ppm for both of them on the productivity of rice plants grown in saline soil. Foliar application of Si at different tested sources and rates significantly increased each of physiological characters (chlorophyll content and stomatal conductance), morphological characters (plant height, number of tillers/ m2, leaf area index and dry matter production/ m2), chemical composition in the leaf (K %, K / Na ratio and Si %), yield components (number of panicles/ m2, panicle weight and length, number of filled grains/ panicle and 1000 - grain weight), yields/ ha (grain and straw), grain quality characters (hulling % , milling % , head rice %, protein and amylose %), while significantly decreased Na % in the leaf, number of unfilled grains/ panicle and chalkiness grains % as compared with untreated plants (control treatment) in both seasons. Spraying of nano silica at 150 ppm and potassium silicate at 1500 ppm were found to be more efficiency in increasing most abovementioned traits of rice plants grown in saline soil than the other tested silicon sources and rates.

B. ZAYED, S. BASSIOUNI, A. OKASHA, M. ABDELHAMED, S. SOLTAN, and M. NEGM Citation: Zayed B, Bassiouni S, Okasha A, Abdelhamed M, Soltan S, Negm M (2023). Path coefficient, eigenvalues, and genetic parameters in Egyptian rice (Oryza sativa L.) under aerobic conditions. SABRAO J. Breed. Genet. 55(1): 131-145. http://doi.org/10.54910/sabrao2023.55.1.13. Summary

Two field experiments were conducted at the Experimental Farm of Sakha Agricultural Research Station, Kafr EL Sheikh, Egypt during 2018 and 2019 rice growing seasons, to study the effect of three sowing dates viz; April 20th, May 5th and May 20th, three seedling ages namely; 20, 30 and 40 days and male rows direction; one and two directions on out crossing of hybrid rice seed production of the CMS line IR69625A crossed by the male line Giza 178R. Split-split plot design with three replications was used. The main plots were devoted to the sowing dates, while the seedling ages were arranged in the sub plots and male rows direction were arranged in the sub-sub plots. The results showed that the interaction between sowing dates and seedling ages had a significant effect on number of days to 50% heading, plant height (cm), panicle length (cm) and panicle exertion (%), however, these traits didn't significantly affected by male rows direction. On the other hand, panicle weight (g), number of filled grains panicle-1, seed set (%), harvest index (%) and seed yield (t ha-1) were significantly affected by sowing dates, seedling ages and male rows direction. The interactions among sowing dates, seedling ages and male rows direction had highly significant effect on seed yield. The highest values of seed yields were obtained when rice plants were sowing on April, 20 with seedling age 20 days in two rows direction during 2018 and 2019 seasons.