Tracking and Monitoring Leaf Development, Coupling Law and Regulation Techniques during Flowering Period of Hybrid Foxtail Millet (<i>Setaria italica</i>(L.) P. Beauv.) Parental Lines

The determining factor of Setaria italica (L.) P. Beauv. is the coupling of its flowering stage and outcrossing rate which leads to low and unstable seed yields in self-pollinated foxtail millet hybrids and thereby limits their large-scale application. In this study, Datong 27, Datong 29 and gu 83 were screened and identified through meticulous observations of their pollination habitats. High exposure rate, degree of exposure and plump of stigma are good factors to accept foreign pollen. Datong 27 and Datong 29 have some additional characteristics, such as long filaments and exposed and full anthers that contain a large amount of pollen. We transformed into a series of stigma-exposed and plump sterile lines that easily accepted exotic pollen. New restorer lines with anthers that were full of powder and exhibited quick recovery, which improved the parental lines’ heterosexual characteristics. By tracking and monitoring the leaf development of the new sterile and restorer lines, a coupling law of leaf development was determined and a series of flowering control measures were formulated. These factors ensured that the parental lines encounter one another during the flowering stage. By utilizing fertilizer and water, the vitality of the female stigma, amount of powder scattered and powder loosening time were prolonged, which increased hybrid seed yields from 1500 to 3000 kg/hm2. These findings were helpful in resolving the technical problems of seed production that restricted the propagation of foxtail millet hybrids and supporting future large-scale applications.

Genetic Diversity and Classification of Chinese Elite Foxtail Millet [Setaria italica (L.) P. Beauv.] Revealed by Acid-PAGE Prolamin

Arid and semi-arid regions of China account for more than half of the country. Because of drought resistance and high nutritive value, elite foxtail millet (Setaria Italica (L.) P. Beauv.) is one of the most important cereal crops in China. Evaluation of germplasm and genetic diversity of foxtail millet is still in its infancy, but prolamin could play an important role as a protein marker. To investigate the genetic diversity and population structure of foxtail millet from different ecological zones of China, 90 accessions of foxtail millet were collected from three major ecological areas: North, Northwest, and Northeast China. The prolamin contents were examined by acid polyacrylamide gel electrophoresis (acid-PAGE). Five to twenty-two prolamin bands appeared in tested varieties, of which were polymorphic, so prolamin patterns of foxtail millet varieties can be used in variety identification and evaluation. Structure analysis identified six groups, which matches their pedigree information but not their geographic origins. This indicated a high degree (87.78%) of consistency with a phylogenetic classification based on SSR. The results showed prolamin banding patterns were an effective method for analyzing foxtail millet genetic variability.

Transcriptome Analysis of oserf922 Mutants Reveals New Insights into Rice Blast Resistance

Rice blast disease,caused by fungal Magnaporthe oryzae,severely threatens food security.The susceptibility(S) genes have emerged to support pathogenesis,and disruption of S gene usually confers increased resistance to multiple pathogen isolates.Rice ethylene response factor gene Os ERF922 is a potential S gene in blast disease.However,how Os ERF922 negatively regulates resistance against M.oryzae is still unknown.

Moderate drought alleviates the damage to grain quality at high temperatures by improving the starch synthesis of inferior grains in japonica rice

In agricultural production,temperature and moisture are important factors affecting grain yield and quality.Although moderate drought at the grain-filling stage can effectively alleviate the damage caused by high temperature,the specific regulatory mechanism driving the effect of moderate drought at the high temperature on starch synthesis is still unclear.To explore the effects and mechanisms of high temperature and moderate drought on rice starch synthesis at the grainfilling stage,the activities of enzymes and expression levels of the genes involved in starch synthesis under four different treatments involving high temperature and/or water stress(CK,HT,WS,and HT+WS)were investigated in this study.The starch synthesis of a japonica inbred rice was measured under the four treatments during the grain filling.The results show that the effects of high temperature and moderate drought on grain filling mainly occur in the inferior grains of rice.Through the regulation of enzymes involved in starch synthesis and the expression levels of their main genes,the synthesis of rice starch can be affected.Therefore,the high temperature and moderate drought were antagonistic,and moderate drought can alleviate the damage to grain quality at a high temperature by improving the starch synthesis of inferior grains in japonica rice.This study provides a basis for stress-resistance cultivation and breeding strategies of rice with high temperature tolerance.

Genome-edited ATP BINDING CASSETTE B1 transporter SD8 knockouts show optimized rice architecture without yield penalty

Dear editor,In the 1960s,the use of semi-dwarf rice and wheat varieties ushered in the‘‘Green Revolution,’’leading to reduced lodging and increased harvest index.In rice,essentially all modern semidwarf varieties carry a specific null mutation or weak alleles of Semi-Dwarf1(SD1),which encodes a GA20-2 oxidase in the gibberellin biosynthetic pathway(Monna et al.,2002;Sasaki et al.,2002;Spielmeyer et al.,2002).In addition to gibberellins,other plant hormones such as brassinosteroids,strigolactones,and auxin also function in reducing rice height(Ferrero-Serrano et al.,2019).However,many dwarf or semi-dwarf mutants have not been widely used in rice-breeding programs because they adversely impact grain yield(Ferrero-Serrano et al.,2019).