Yield, Yield Components and Nutritional Traits Values of Biofortified Sorghum Hybrids in Mali

To assess the adaptation, yield potential, nutrient content and to identify the traits contributing directly and indirectly to yield increase, a two years’ study was conducted in four locations. Thus, a total of 28 F1 hybrids from two females and 14 male parents, were developed and used in this study along with the parents and four commercial hybrids. Seven (7) hybrids were identified with grain yield ranging from 4015 to 4624 kg-1ha; heading from 64 to 92 days; iron content from 8.63 to 91.15 ppm; Zinc content from 8.14 to 28.71 ppm; lysine content from 2.73 to 5.61 mg/100g; threonine content from 2.50 to 6.28 mg/100g. For both phenotypic and genotypic levels, a significant correlation on grain yield through plant height, panicle length, primary branch per panicle, grain number per panicle and number of whorls per panicle were found. Based on the path analysis, positive and significant direct and indirect effect of correlation were observed in this work for a cycle, grain quality, panicle length, primary branch per panicle, grain number per panicle and number of whorls per panicle at the phenotypic level.

Down-expression of TaPIN1s Increases the Tiller Number and Grain Yield in Wheat

Background Tiller number is a factor determining panicle number and grain yield in wheat (Triticum aestivum). Auxin plays an important role in the regulation of branch production. PIN-FORMED 1 (PIN1), an auxin efflux carrier, plays a role in the regulation of tiller number in rice (Oryza sativa); however, little is known on the roles of PIN1 in wheat. Results Nine homologs of TaPIN1 genes were identified in wheat, of which TaPIN1-6 genes showed higher expression in the stem apex and young leaf in wheat, and the TaPIN1-6a protein was localized in the plasma membrane. The down-expression of TaPIN1s increased the tiller number in TaPIN1-RNA interference (TaPIN1-RNAi) transgenic wheat plants, indicating that auxin might mediate the axillary bud production. By contrast, the spikelet number, grain number per panicle, and the 1000-grain weight were decreased in the TaPIN1-RNAi transgenic wheat plants compared with those in the wild type. In summary, a reduction of TaPIN1s expression increased the tiller number and grain yield per plant of wheat. Conclusions Phylogenetic analysis and protein structure of nine TaPIN1 proteins were analyzed, and subcellular localization of TaPIN1-6a was located in the plasma membrane. Knock-down expression of TaPIN1 genes increased the tiller number of transgenic wheat lines. Our study suggests that TaPIN1s is required for the regulation of grain yield in wheat.

OsSPL9 Regulates Grain Number and Grain Yield in Rice

Rice grain yield consists of several key components, including tiller number, grain number per panicle (GNP), and grain weight. Among them, GNP is mainly determined by panicle branches and spikelet formation. In this study, we identified a gene affecting GNP and grain yield, OsSPL9, which encodes SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) family proteins. The mutation of OsSPL9 significantly reduced secondary branches and GNP. OsSPL9 was highly expressed in the early developing young panicles, consistent with its function of regulating panicle development. By combining expression analysis and dual-luciferase assays, we further confirmed that OsSPL9 directly activates the expression of RCN1 (rice TERMINAL FLOWER 1/CENTRORADIALIS homolog) in the early developing young panicle to regulate the panicle branches and GNP. Haplotype analysis showed that Hap3 and Hap4 of OsSPL9 might be favorable haplotypes contributing to high GNP in rice. These results provide new insights on high grain number breeding in rice.

Lanthanum (La) improves growth, yield formation and 2-acetyl-1-pyrroline biosynthesis in aromatic rice (Oryza sativa L.)

Background Lanthanum (La) is a rare earth element that can influence plant growth and development. However, the effect of La on growth, yield formation and 2-acetyl-1-pyrroline (2-AP, a key compound responsible for the aroma of rice) biosynthesis in aromatic rice (Oryza sativa L. subsp. japonica Kato) has not been reported. Therefore, the present study investigated the effects of La on growth, photosynthesis, yield formation and 2-AP biosynthesis in aromatic rice through three experiments. Results Two pot experiments and a two-year field trial were conducted with different rates of La application (20–120 LaCl3 mg kg−1 and 12 kg ha−1 LaCl3), and treatments without La application were used as controls. The results showed that the application of LaCl3 at 80 and 100 mg kg−1 and at 12 kg ha−1 greatly increased the 2-AP content (by 6.45–43.03%) in aromatic rice seedlings and mature grains compared with the control. The La treatments also increased the chlorophyll content, net photosynthetic rate and total aboveground biomass of rice seedlings. Higher antioxidant enzyme (superoxide, peroxidase, and catalase) activity was detected in the La treatments than in the control. The La treatments also increased the grain yield, grain number per panicle and seed-setting rate of aromatic rice relative to the control. Moreover, the grain proline and γ-aminobutyric acid contents and the activity of betaine aldehyde dehydrogenase significantly decreased under the La treatment. The application of La to soil enhanced the activity of proline dehydrogenase by 20.62–56.95%. Conclusions La improved the growth, yield formation and 2-AP content of aromatic rice and enhanced 2-AP biosynthesis by increasing the conversion of proline to 2-AP and decreasing the conversion of GABald to GABA.

Uncovering the genetic mechanisms regulating panicle architecture in rice with GPWAS and GWAS

Background The number of panicles per plant, number of grains per panicle, and 1000-grain weight are important factors contributing to the grain yield per plant in rice. The Rice Diversity Panel 1 (RDP1) contains a total of 421 purified, homozygous rice accessions representing diverse genetic variations within O. sativa. The release of High-Density Rice Array (HDRA, 700 k SNPs) dataset provides a new opportunity to discover the genetic variants of panicle architectures in rice. Results In this report, a new method genome-phenome wide association study (GPWAS) was performed with 391 individuals and 27 traits derived from RDP1 to scan the relationship between the genes and multi-traits. A total of 1985 gene models were linked to phenomic variation with a p-value cutoff of 4.49E-18. Besides, 406 accessions derived from RDP1 with 411,066 SNPs were used to identify QTLs associated with the total spikelets number per panicle (TSNP), grain number per panicle (GNP), empty grain number per panicle (EGNP), primary branch number (PBN), panicle length (PL), and panicle number per plant (PN) by GLM, MLM, FarmCPU, and BLINK models for genome-wide association study (GWAS) analyses. A total of 18, 21, 18, 17, 15, and 17 QTLs were identified tightly linked with TSNP, GNP, EGNP, PBN, PL, and PN, respectively. Then, a total of 23 candidate genes were mapped simultaneously using both GWAS and GPWAS methods, composed of 6, 4, 5, 4, and 4 for TSNP, GNP, EGNP, PBN, and PL. Notably, one overlapped gene (Os01g0140100) were further investigated based on the haplotype and gene expression profile, indicating this gene might regulate the TSNP or panicle architecture in rice. Conclusions Nearly 30 % (30/106) QTLs co-located with the previous published genes or QTLs, indicating the power of GWAS. Besides, GPWAS is a new method to discover the relationship between genes and traits, especially the pleiotropy genes. Through comparing the results from GWAS and GPWAS, we identified 23 candidate genes related to panicle architectures in rice. This comprehensive study provides new insights into the genetic basis controlling panicle architectures in rice, which lays a foundation in rice improvement.

Down-expression of TaPIN1s Increases the Tiller Number and Grain Yield in Wheat

Background: Tiller number is a factor determining panicle number and grain yield in wheat (Triticum aestivum L.). Auxin plays an important role in the regulation of branch production. PIN-FORMED 1 (PIN1), an auxin efflux carrier, plays a role in the regulation of tiller number in rice (Oryza sativa); however, little is known on the roles of PIN1 in wheat. Results: Nine homologs of TaPIN1 genes were identified in wheat, of which TaPIN1-6 genes showed higher expression in the stem apex and young leaf in wheat, and the TaPIN1-6a protein was localized in the plasma membrane. The down-expression of TaPIN1s increased the tiller number in TaPIN1-RNA interference (TaPIN1-RNAi) transgenic wheat plants, indicating that auxin might mediate the axillary bud production. By contrast, the spikelet number, grain number per panicle, and the 1000-grain weight were decreased in the TaPIN1-RNAi transgenic wheat plants compared with those in the wild type. Conclusions: Phylogenetic analysis and expression patterns of nine TaPIN1 genes, and their protein structures and subcellular localization of TaPIN1-6a protein were analyzed. Down-regulated expression of TaPIN1 genes increased the tiller numbers of transgenic wheat lines. Our study suggests that TaPIN1s is required for the regulation of grain yield in wheat.

Evaluation of rice genotypes for growth, yield and yield components

Twelve rice genotypes were evaluated under irrigated lowland and upland rainfed conditions in a randomized complete block design with three replications at Khumaltar, Lalitpur, Nepal in 2019. Data on plant height, panicle length, effective tillers per plant, fertile grain number per panicle and grain yield were taken. The variation was observed for plant height, panicle length, effective tillers per plant, fertile grain number per panicle among the evaluated rice genotypes. The rice genotype NR 11375-B-B-21 produced the highest grain yield (3974.75 kg/ha) followed by NR 11374-B-B-23 (3615.26 kg/ha) and NR 11145-B-B-B-6 (3597.56 kg/ha) under irrigated low land condition. Similarly, the rice genotypes, NR 11375-B-B-21 produced the highest grain yield (3837.15 kg/ha) followed by NR 11321-B-B-7-3 (3588.71 kg/ha) and NR 11305-B-B-1-3 (3292.36 kg/ha) under upland rainfed condition. The combined analysis showed that rice genotype NR 11375-B-B-21 produced the highest grain yield (3905.95 kg/ha) followed by NR 11374-B-B-23 (3494.63 kg/ha), and NR 11321-B-B-7-3 (3409.89 kg/ha) respectively. Thus, after evaluation of yield, two genotypes namely NR 11375-B-B-21, NR 11374-B-B-23, were selected as outstanding genotypes, which can be used as potential breeding materials for upland and low land environments of mid hills of Nepal.

Effects of potassium on panicle structure and spikelet morphology of a double grained rice cultivar

Influence of K on panicle structure and spikelet morphology of a double grained rice cultivar was evaluated. Results showed that K enhanced the plant height, leaf number, yield and yield contributing descriptors in double grained rice cultivar. The ratio of single-double grained spikelets on a panicle varied from 70 : 30 to 59 : 41. The position of spikelets on a panicle viz. primary vs. secondary branch, middle vs. upper or lower portion of panicle, had little effect on single-double grain ratio. However, K significantly affected the single-double grained spikelet ratio between primary and secondary branches. Multi-grained spikelets showed the potential to increase grain number per panicle thereby increasing rice yield.

Seleksi Generasi Awal untuk Toleransi terhadap Suhu Tinggi pada Padi

The impacts of high-temperature stress on rice growth and productivity can be mitigated by growing tolerant varieties. This research was conducted to estimate the genetic parameters and to select the best genotypes based on the susceptibility stress index (SSI) values. This research was conducted from August 2016 to February 2017. Half of the five weeks seedling tiller of each F3 plant was transferred to new pot culture so that each genotype of the F3 rice population grown in two pots. At the maximum vegetative phase, the parental and F3 populations were treated under two different temperatures: in the open ground area and inside a greenhouse with daily mean temperatures of 38.89/22.67 °C dan 41.62/23.32 °C, respectively. The traits observed were yield and yield components. The results showed that the grain yield of the parents and the F3 population were lower when grown inside the greenhouse. The filled grain number per panicle was controlled by additive gene action in these two environments, and is suggested to be a selection character. Selection based on SSI index obtained 13 genotypes tolerant to heat stress and had higher yield compared to their parents. SSD method combined with shuttle breeding is recommended as a breeding method to produce tolerant and high yielding lines. Keywords: heat stress, heritability, segregating population, SSI