DEGENERATED LEMMA (DEL) Is a New Allele of OsRDR6 That Regulates Lemma Development and Affects Rice Grain Yield

The lemma and palea are floral organ structures unique to grasses, and their development affects grain size. However, information on the molecular mechanism of lemma development is limited. In this study, we investigated a rice spikelet mutant, degenerated lemma (del), which developed florets with a slightly degenerated or rod-like lemma. The results indicate that the mutation of the DEL gene interfered with lemma development. In addition, del also showed a significant reduction in grain length and width, seed setting rate, and 1000-grain weight, which led to a reduction in yield. The results indicate that the mutation of the DEL gene further affects rice grain yield. Map-based cloning shows a single-nucleotide substitution from T to A within Os01g0527600/DEL, causing an amino acid mutation of Leu-34 to His-34 in the del mutant. DEL is an allele of OsRDR6, encoding the RNA-dependent RNA polymerase 6, and is highly expressed in the spikelet. RT-qPCR results show that the expression of some floral organ identity genes was changed, which indicates that the DEL gene regulates lemma development by modulating the expression of these genes. The present results suggest that DEL plays an important role in lemma development and rice grain yield.

Introgression Progress for Phenotypic Traits and Parent-progeny Diversity at Advanced Segregation Population From Oryza Barthii and Oryza Glaberrima/oryza Sativa Crosses

Rice is a cereal staple of global fame and importance. Oryza barthii, a wild species holds significant traits and its utilization in rice breeding is rare. This study traced introgression trend of heritable traits in the offspring of O. barthii with an Africa-Asian progenitor to F8 and assessed diversity between the parents and the F8 population. Significant (P<0.05) genotypic variation existed for all the traits except tiller number, panicle/meter squared, grains/panicle and 1000 grain weight. Grains/panicle and days to 50% flowering had respective least (3.34%) and highest (96.32%) broad sense heritabilities. All traits had lower GCV compared to PCV. The least (5.28% and 8.05%) and the highest (90.8% and 98.1%) GCV and PCV were respectively from grains/panicle and tiller number. Clear variations on the panicles and grains include: variations in sizes, shapes, colours, presence or absence of awns. The total variance explained by five principal component axes was 80.1%. Plant height at maturity was the only trait with significant (p ≤ 0.01) correlation and regression between F6 and F7. Progenies resemblance to Parent 1(IRGC 104084) retrogressively declined but parent-offspring to parent 2 (TGS 25) progressively increased from F6 to F8. Three visible groups of rice type in this study were: the O. barthii (11%), O. sativa (67%) and the intermediate group (22%). This research has added to rice genetic resources; an investigation of the nutritional status of the progenies would be an interesting research.

Performance of double grained rice cultivar under different plant spacing

Plant spacing ensures uniform and optimum plant population and facilitates sufficient natural resources for crop growth which, in turns influences the crop yield positively. An investigation was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, during July to December 2017 to study the influence of plant spacing on the yield of double grained rice cultivar. The study comprised five spacing viz. 25 cm × 15 cm, 25 cm × 10 cm, 20 cm × 15 cm, 20 cm × 10 cm and 15 cm × 15 cm and two rice cultivars viz. a double grained rice cultivar and BRRI dhan49 and a double grained rice cultivar. It was laid out in a randomized complete block design with three replications. The double grained rice cultivar produced taller plant (155.65 cm), longer panicle (23.93 cm), higher 1000-grain weight (25.96) and higher straw yield (6.90 t ha-1), though the higher grain yield (3.68 t ha-1) was found in the test cultivar (BRRI dhan49). Planting at 20 cm × 15 cm produced the highest grain yield (3.70 t ha-1) which was at par with 25 cm × 15 cm, 25 cm × 10 cm and 20 cm × 10 cm while planting at 15 cm × 15 cm produced the lowest grain yield (3.13 t ha-1). The interaction of the double grained rice cultivar with all spacing combinations produced taller plants than the spacing combinations with BRRI dhan49. The higher grain yield (3.52 t ha-1) was found in the double grained rice cultivar with 20 cm × 10 cm spacing which was at par with the spacing of 20 cm × 15 cm and 25 cm × 15 cm, respectively; although BRRI dhan49 always produced the higher yield. The lowest grain yield (3.08 t ha-1) was recorded at the double grained rice cultivar with 25 cm × 10 cm spacing, however, the same treatment produced the highest biological yield (11.23 t ha-1) due to the highest straw yield (8.15 t ha-1). Hence, the spacing 20 cm × 15 cm might be recommended for the higher grain yield in the double grained rice cultivar Res. Agric., Livest. Fish.8(3): 273-279, December 2021

Statistical modeling for analyzing grain yield of durum wheat under rainfed conditions in Azad Jammu Kashmir, Pakistan

One of the most important traits that plant breeders aim to improve is grain yield which is a highly quantitative trait controlled by various agro-morphological traits. Twelve morphological traits such as Germination Percentage, Days to Spike Emergence, Plant Height, Spike Length, Awn Length, Tillers/Plant, Leaf Angle, Seeds/Spike, Plant Thickness, 1000-Grain Weight, Harvest Index and Days to Maturity have been considered as independent factors. Correlation, regression, and principal component analysis (PCA) are used to identify the different durum wheat traits, which significantly contribute to the yield. The necessary assumptions required for applying regression modeling have been tested and all the assumptions are satisfied by the observed data. The outliers are detected in the observations of fixed traits and Grain Yield. Some observations are detected as outliers but the outlying observations did not show any influence on the regression fit. For selecting a parsimonious regression model for durum wheat, best subset regression, and stepwise regression techniques have been applied. The best subset regression analysis revealed that Germination Percentage, Tillers/Plant, and Seeds/Spike have a marked increasing effect whereas Plant thickness has a negative effect on durum wheat yield. While stepwise regression analysis identified that the traits, Germination Percentage, Tillers/Plant, and Seeds/Spike significantly contribute to increasing the durum wheat yield. The simple correlation coefficient specified the significant positive correlation of Grain Yield with Germination Percentage, Number of Tillers/Plant, Seeds/Spike, and Harvest Index. These results of correlation analysis directed the importance of morphological characters and their significant positive impact on Grain Yield. The results of PCA showed that most variation (70%) among data set can be explained by the first five components. It also identified that Seeds/Spike; 1000-Grain Weight and Harvest Index have a higher influence in contributing to the durum wheat yield. Based on the results it is recommended that these important parameters might be considered and focused in future durum wheat breeding programs to develop high yield varieties.

Effects of Potassium Silicate Fertilizer on Photosynthetic Characteristics and Yield in Winter Wheat (Triticum Aestivum L.)

Effects of different dosages of potassium silicate fertilizer on photosynthetic characteristics and yield of winter wheat under field conditions were studied. Four different dosages: 0, 45, 90 and 135kg/ha were applied. Results showed that the chlorophyll content, net photosynthetic rate of wheat flag leaf firstly increased and then decreased with the increase of levels of potassium silicate fertilizer. By the change of SPAD values after flowering, when the application of potassium silicate fertilizer was 90 kg/ha, the existence time of chlorophyll in flag leaf was significantly long, and the net photosynthetic rate was significantly increased. The 1000-grain weight of winter wheat significantly increased and the yield the highest. Overall, when the applied amount of potassium silicate fertilizer was 90 kg/ha, the performances of winter wheat were best. Bangladesh J. Bot. 50(4): 1127-1132, 2021 (December)

Evaluation of sowing methods and nitrogen levels for grain yield and components of durum wheat under arid region of Egypt

The present experiment was conducted at private farm during 2018/19 and 2019/20 seasons. The investigated area lies within the extremely arid belt, having long hot summer and short warm winter. The main goal of this investigation was to evaluate the effect of different sowing methods on yield components of wheat, using split plot design with three replications. Sowing methods in main plot were broadcasting method, row spacing 10, 15 and 20 cm apart). Nitrogen fertilizer levels in sub plot were 60, 75 and 90 kg N fed-1 (fed = 4200 m-2). The increase percentage due to row spacing at 20 cm apart (M4) compared to broadcasting method (M1) were (23.30 & 26.74%) for spike length; (5.11 & 6.94 %) for 1000 grain weight and (8.02 & 7.74%) for grain yield and according ally (3.07 & 3.08%) for harvest index in both seasons, respectively. Overall, from the present study the sowing method in rows with 20 cm apart and the optimum N fertilizer rate (90 kg fed-1) for durum wheat production in the soils of Qasir, Dakhala oasis on silt loam soil was the best treatment.

Correlation between quantitative traits that affect grain yield of maize hybrids

The selection of pairs for hybridization requires knowledge about the correlation of the most important quantitative traits that affect grain yield of maize hybrids. The current study was carried out in the Agricultural Research Center “Donskoy” located in the south of the Rostov region with unstable moisture. The years of study (2018–2020) were arid (HThC 0.32–0.89). The purpose of the current study was to evaluate the correlation between quantitative traits and their influence on grain yield of maize hybrids under arid conditions. The objects of research were 96 interline maize hybrids. The analysis has identified the correlation between grain yield and such quantitative traits as ‘one maize ear weight’ (r = 0.64...0.87), ‘number of grains per one maize ear row’ (r = 0.37...0.75), ‘number of grains per maize ear’ (r = 0.32...0.51), ‘number of maize ears per plant’ (r = 0.41...0.53), ‘grain yield’ (r = 0.45...0.64). The traits ‘1000-grain weight’ and ‘number of grain rows’ had either no or slight effect on the formation of grain yield of maize hybrids (r = -0.12...0.28). There have been established the traits, the high values of which were well-combining in one genotype. The values of the trait ‘one maize ear weight’ raised due to an increase of the trait ‘number of grains per one maize ear row’ (r = 0.27...0.74), ‘number of grains per maize ear’ (r = 0.26...0.55), ‘grain yield’ (r = 0.21...0.52). The trait ‘number of grains per maize ear’ raised with an increase in the values of such constituent components as ‘number of grains per one maize ear row’ (r = 0.70...0.76), ‘number of grain rows per maize ear’ (r = 0.59...0.66), and also with an increase of ‘number of maize ears per plant’ (r = 0.32...0.51) and ‘grain yield’ (r = 0.36...0.38). There have been identified difficulty-combining quantitative traits, when the value of the trait ‘1000-grain weight’ decreased with the increase of the ‘number of grain rows per maize ear’ (r = – 0.18...-0.56), ‘number of grains per a maize ear row’ (r = -0.15...-0.31) and ‘grain yield’ (r = -0.01...-0.36).

Evaluation of Different Land Preparation Techniques for Preparing Medium Textured Soil in Rice Production under Agro-Ecological Conditions of Sheikhupura-Pakistan

Tillage is an important factor affecting different soil properties and crop yields. Tillage relates to applying forces to soil using different implements for preparation of a proper seed bed. For rice crop, land preparation is a rigorous and time consuming operation that needs special attention for preparing a puddled soil condition to transplant the weak and tender rice seedlings. A field experiment was established under agro-ecological conditions of Sheikhupura to evaluate different land preparation techniques during fall in 2017 and 2018 years. The experiment was performed at Adaptive Research Farm Sheikhupura. It was laid out in randomized complete block design (RCBD) with four different land preparation techniques including T1= Cultivator (4 times) + Planking (2 times) (Farmer’s Practice), T2=MB plough (1 time) + Disc Harrow (1 time) + Planking (2 Times), T3=MB plough (1 time) + Cultivator (2 times) + Planking (2 Times) and T4= Rotavator (1 time) + Disc Harrow (1 time) + Planking (2 Times), each treatment replicated thrice during both the years. All the other agronomic and crop husbandry operations were kept uniform throughout the growing season every year. The results revealed that preparing land with MB plough (1 time), Disc Harrow (1 time) and Planking (2 times) is the best land preparation method can increase the paddy yield 13.5-17.5% as compared to the traditional method practised by the farmers. Moreover, highest plant height (134.00 cm and 132.00 cm), number of tillers (224 and 220 m-2), number of grains per spike (130 and 116) and 1000-grain weight (23.0 and 22.0 g) respectively during Kharif-18 and Kharif-19 was also recorded in the same treatment. So, preparation of land for paddy in agro-ecological conditions of Sheikhupura using MB plough (1 time), Disc Harrow (1 time) and Planking (2 times) can significantly enhance the paddy yield.

Effect of the fortilizer nitrophoska on sorghum Sorghum bicolor L. parasitized by witchweed (Striga Hermonthica Del Benth)

Effect of the fortilizer nitrophoska on sorghum Sorghum bicolor L. parasitized by witchweed (Striga Hermonthica Del Benth) Nitrophoska (NPK), a compound fertilizer, showed significant effects in stimulating yield components of Sorghum bicolor L. cultivar Tabat and in depressing the parasitism of Striga hermonthica Del. Benth. Over all treatments nitrophoska at N3 (54 kg N/F) gave 160, 105,121 and 120% increases in yield components over the control for head weight, plant height, 1000 grain weight and straw yield/ m2 of sorghum. Nitrophoska scored 83% and 80% decrease in striga dry shoot weight / m2 and striga density / m2, respectively less than the control at N1 (18 kg N/F). To maximize the yield components of sorghum, higher levels of nitrophoska (N2. N3) were recommended to be used; while lower levels of nitrophoska (N1) were recommended to combat the menace of striga in fields of sorghum

Performance of Transplant Aus Rice Varieties under Different Nitrogen Management Practices

Management of applied nitrogen in rice field is one tool that could lead to increase in rice yield, but often ignored by most farmers. The experiment was carried out from April to July 2015 at the Agronomy Field Laboratory of Patuakhali Science and Technology University, Dumki, Patuakhali to find out the influence of different nitrogen management and variety on the yield performance of transplant Ausrice. The study consisted of four levels of nitrogen viz. Control (without N), 30 kg N ha-1, 60 kg N ha-1 and urea super granule @ 52 kg N ha-1 and four Transplanted aus rice varieties viz. KaliHitta, ChaitaBoro, Abdul Hai and Gota IRRI, and was laid out in a split-plot design with three replications. The levels of nitrogen were assigned in the main plot and varieties were allocated in the sub-plots. Nitrogen management, variety and their interactions exerted significant (P ≤ 0.05) influence on plant characters, yield contributing characters and yield of transplanted Aus rice. In the case of nitrogen management, the tallest plant was 161.60 cm, maximum leaf area index(2.97, the highest number of effective tillers hill-115, longest panicle 24.30 cm with the maximum number of filled grains as94.73, 1000-grain weight gave 29.97 g. Grain yield of 2.48 t ha-1 were obtained from USG @ 52 kg N ha-1 and the shortest plant height of 136.90 cm with lowest leaf area index of 1.78, lowest number of effective tillers hill-1 (8.43), shortest panicle (18.84 cm) with the lowest numbers of filled grains panicle-1 (53.18), 1000-grain weight (24.33 g) and grain yield (1.40 t ha-1) were obtained in control (N1=O, kg N ha-1). Among the varieties, ChaitaBoro gave the tallest plant height (151.60 cm) and maximum leaf area index (2.54). While the highest number of effective tillers hill-1 (12.20), longest panicle (22.42 cm) with the maximum number of filled grains panicle-1 (73.50), highest 1000-grain weight (27.41 g) and highest grain yield (2.39 t ha-1) were recorded from Gota IRRI than other varieties. In case of interaction, Gota IRRI Fertilized with USG at 52 kg N ha-1 produced the highest number of effective tillers hill-1 (16.87), panicle length (25.13 cm), number of grains panicle-1 (105.70) and grain yield (3.13 t ha-1). The lowest number of effective tillers hill-1 (8.13), lowest panicle length (17.47 cm) with minimum numbers of filled grains 47.67) and grain yield (1.12 t ha-1) were produced by the interaction of control (N1=O, kg N ha-1) and Kali Hitta. So, cultivation of transplant Aus rice (Gota IRRI) appeared to be the best performance with USG @ 52 kg N ha-1 and recommended to the end users.