F1 Rice Research Articles

Elucidating the components of genetic variation and genetic parameters for selected quantitative attributes in F1 rice genotypes

Elucidating the components of genetic variation and genetic parameters for selected quantitative attributes in F1 rice genotypes

Test Of Hundreds Established Hybrid Rice Seed Derivatives P-05 And Quantity Of Cemeti Inbrid Rice Derivatives On Product Quality And Quantity

This study aims to determine the combination of treatment of ratoon derived from F1 rice seeds (Hybrid) of Mapan P-05 and ratoon derived from rice seeds (Inbred) whip with various spacings on the quality and quantity of which yield is the best and to know the interaction factors of ratoon derived from Mapan hybrid rice seeds. P-05 and whip inbred rice were the best in terms of yield quality and quantity. Held from December 2021 to June 2022. And planting of ratoons was carried out on November 14, 2021-March 31, 2022. This research was carried out in Sumberharjo Village, Prambanan District, Sleman Regency, Special Region of Yogyakarta. This study used a Completely Randomized Block Design (RAKL) factorial. The first factor is ratoon rice with two varieties and the second factor is the treatment of various spacings of 20x20;25x25;30x30 cm. Data analysis used ANOVA with a level of 5% and 1%, if it had a significant effect, it was followed by a significant difference test (DMRT) with a level of 5%. The results showed that the hybrid variety treatment always showed higher yield quality and quantity than the whip inbred with spacing treatment. 20x20 cm and followed by a spacing of 25x25 cm and 30x30 cm from the Inbred cemeti variety. The combination of hybrid varieties treatment with 20x20 cm spacing gave the heaviest results on the average weight of dry grain harvested per plot, weight of dry grain storage per plot, weight of 1000 grains of grain, weight of dry grain harvested.

The telomere-to-telomere gap-free genome of four rice parents reveals SV and PAV patterns in hybrid rice breeding.

The telomere-to-telomere gap-free genome of four rice parents reveals SV and PAV patterns in hybrid rice breeding.

Genetic variability studies in F1 rice (Oryza sativa L.) hybrids for yield and quality traits

Analysis of variance among lines, significant differences was observed for plant height, number of productive tillers per plant, panicle length, number of filled grains per panicle, single plant yield and 1000 grain weight while days to 50 per cent flowering, plant height, panicle length, single plant yield, 1000 grain weight, milling per cent, head rice recovery, grain length, L/B ratio, kernel length after cooking, kernel breadth after cooking, breadth wise elongation ratio and amylose content exhibited significant differences among testers besides in L x T interaction, all characters along with yield. The magnitude of difference between genotypic coefficient of variation (GCV) and phenotypic coefficient of variation was less for the traits indicating slight influence of environment. A wide range of PCV (4.09 – 43.43 %) and GCV (6.58 – 43.39 %) was resulted for 19 traits. The presence of higher GCV and PCV observed in number of filled grains per panicle followed by single plant yield, Alkali spreading value, gel consistency and amylose content, which signifies the additive genetic control in inheritance of that trait. The presence of high scale of GCV and PCV for observed traits suggested having better possibility for the enhancement through simple selection procedure.

RESPON PERTUMBUHAN DAN HASIL LIMA GENOTIP PADI HIBRIDA TERHADAP PUPUK ORGANIK TANDAN KOSONG KELAPA SAWIT (TKKS) PADA TANAH ULTISOL

[RESPONSE OF GROWTH AND YIELD OF FIVE RICE HYBRID GENOTYPE ON THE ORGANIC FERTILIZER OF PALM OIL BUNCHES ON ULTISOL]. Oil Palm Bunches (OPB) are solid waste potential as organic fertilizer to improve soil physical, biological and chemical properties, especially on ultisol soils for rice development. This research was conducted in August - November 2019 in Padang Harapan, Bengkulu City. The materials used were F1 rice seeds, OPB organic fertilizer. The experimental design was a factorial Randomized Completely Block Design (RCBD) with 2 factors. The first factor was 5 hybrid genotypes (F1), namely, Kuning x Inpago5, Kuning x Inpago9, Kuning x Inpago6, Arang x Inpago8, and Kuning x Salumpikit. The second factor was the dosage of OPB, namely 0 (control), 10 tonnes/ha, 15 tonnes/ha, and 20 tonnes/ha, the experiment was repeated 3 times. The variables observed were plant height, number of productive tillers, flowering age, harvest age, the total number of fill grains, number of filled grains, number of empty grains, 1000 grain weight, and grain weight/hill. The results showed that there was an interaction between genotype and OPB on the number of tillers. The interaction between the Kuning x Salumpikit genotypes and 10 tonnes/ha of organic fertilizer produced the largest number of tillers. Genotype G3(Kuning x Inpago6) produced the best rice growth and yield. In this study, the optimum point for OPB fertilization on growth and yield of the five genotypes tested had not been obtained.

Clonal seeds from hybrid rice by simultaneous genome engineering of meiosis and fertilization genes.

Heterosis, or hybrid vigor, is exploited by breeders to produce elite high-yielding crop lines, but beneficial phenotypes are lost in subsequent generations owing to genetic segregation. Clonal propagation through seeds would enable self-propagation of F1 hybrids. Here we report a strategy to enable clonal reproduction of F1 rice hybrids through seeds. We fixed the heterozygosity of F1 hybrid rice by multiplex CRISPR-Cas9 genome editing of the REC8, PAIR1 and OSD1 meiotic genes to produce clonal diploid gametes and tetraploid seeds. Next, we demonstrated that editing the MATRILINEAL (MTL) gene (involved in fertilization) could induce formation of haploid seeds in hybrid rice. Finally, we combined fixation of heterozygosity and haploid induction by simultaneous editing of all four genes (REC8, PAIR1, OSD1 and MTL) in hybrid rice and obtained plants that could propagate clonally through seeds. Application of our method may enable self-propagation of a broad range of elite F1 hybrid crops.

An Effort for Producing Disease Free High Yielding F2 Grains from F1 Seeds Evolved through CMS Breeding Technology

CMS A-lines (IR 58025 A) and KMR-3 as R- line were procured from the State Rice Research Station, Chin surah, Hooghly during December 2011. The seeds of A-line and R-line were sown in the seed bed at the research field of the Crop Research Farm (CRF) under The Department of Botany, The University of Burdwan on 18/12/2011 following anorms of CMS breeding technology. These seedlings were transplanted accordingly for raising F2 plant population. These F1 seeds were undertaken for F2 population which was observed critically during its growth and developmental phase till harvesting. These F1 seeds were sown in the seed bed maintaining three types of spacing. Five organic manure treatments viz. T0, T1, T2, T3, T4 were applied in the soil of each variety and spacing sub plot i.e total 30 sub plots were maintained following Randomized Block Design (RBD) in four replications. various metrical characters viz. No. of tillers, No. of total leaves, plant height, No. of tillers bearing inflorescence, total yield per bight were studied critically and recorded all the data carefully for further calculations, no disease occurrence was found in the field of F2 generations. The main aims and objectives of this experimentation were to study the yield attributes and disease free F2 seed from the hybrid F1 rice population evolved through CMS breeding technology.

Inheritance and variability of performance and its major structural components in F1 rice

The aim and tasks of the study . The objective was to study the inheritance of major components of performance in F 1 rice hybrids. To achieve this objective, the dominance degree (hp) and variability (V) were determined for valuable economic characteristics in F 1 of 45 hybrid rice combinations obtained from diallele crossing of 10 rice varieties. Material and methods. The study was conducted on the vegetation plot at the Institute of Rice of NAAS of Ukraine in 2013–2014. Plants of in F 1 hybrids and their parents were structural analyzed: quantitative characteristics: tillering capacity (the number of productive stems), the panicle length, panicle performance (grain weight), grainnumber per panicle, plant performace (grain weight), 1000-grain weight were measured in compliance with the procedures of expert examination and state trials of plant varieties. Results and discussion . The article presents inheritance peculiarities of the major components of rice performance (tillering capacity, panicle length, panicle performance, grainnumber per panicle, plant performance, 1000-grain weight) in F 1 of 45 hybrid combinations by dominance degree. Combinations with overdominancewere distinguished, since an enhancement in expressions of positive changes is expected in subsequent generations, which will contribute to creating productive material for rice breeding. The types of performance dominance and its major structural components (productive tillering capacity, the main panicle length, plant performance, 1000-grain weight) were determined for F 1 of 45 hybrid rice combinations. Conclusions. Five hybrid combinations (Sakha 101 / Giza 177, Sakha 101 / Ukraina-96, Admiral / Lotto, Admiral / Vikont, Vikont / Magic, in which a set of breeding-valuable characteristics isinherited byoverdominance, were singled out. Based on the data obtained, selections from the best hybrid combinations will be conducted to create and further to study productive starting material for rice breeding

Prebreeding selection of rice with colored pericarp based on genotyping Rc and Pb genes

The research was aimed at developing prebreeding resources of Kazakhstan rice varieties with colored pericarp for breeding. During the study, hybrid analysis of inheritance of the trait “colored pericarp” in breeding material used for the work was performed. Rice genotypes with colored pericarp, as well as white rice varieties possessing important breeding traits and maturing under conditions of the republic, were selected from the collection of the Institute of Plant Biology and Biotechnology, Republic of Kazakhstan. Identification of allelic status of Rc (red pericarp) and Pb (anthocyanin pericarp) genes was performed for selected samples using the PCR method. When selecting parental forms for crossing, foreign rice varieties with colored pericarp (Rubin, Mavr, Black rice, etc.) were used as recipient forms. As donors, we used local white rice varieties of Kazakhstan breeding adapted to the soil and climate conditions of rice growing regions (Madina, Marzhan, Bakanasskiy, PakLi) as well as foreign varieties. The ability to set hybrid caryopses and the percentage of sterility were determined in obtained F1 rice hybrids. As a result, the most promising prebreeding material was selected, which will be used for breeding Kazakhstan rice varieties with colored pericarp.

乾田不耕起直播栽培した F1 水稲品種の地上部生育, 押し倒し抵抗値および収量構成要素と品質

乾田不耕起直播栽培した F1 水稲品種の地上部生育, 押し倒し抵抗値および収量構成要素と品質

Identifying the Genes of Blast Resistance in Rice (Oryza sativa L.) Using Line X Tester Analysis

The present study investigation was carried out at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt, during the three successive growing seasons of 2014, 2015 and 2016. Four rice genotypes namely; Sakha 101, Sakha 102, Sakha103 and Sakha 104 were used as Lines and four monogenic lines; i.e., IRBLKS-S, IRBL3-CP4, IRBL5-M and IRBL7-M, were used as Testers, which cried blast resistance genes Pik-s, Pi3, Pi5(t) and Pi7(t). Under field condition, the results showed that the varieties Sakha 102 and Sakha 103 were resistant to blast under the three locations, Sakha, Gemmiza and Zarzoura. On the contrary, the other two Egyptian varieties Sakha 101 and Sakha104 were susceptible. Moreover, the monogenic lines (IRBLKS-S, IRBL3-CP4, IRBL5-M and IRBL7-M) were blast resistant under natural infection conditions. On the other hand, under five artificial inoculations races IA-77, IG-1, ID-15, IC-17 and IB-45 of Magnaporthe grisea, the results revealed that Sakha 102 and Sakha 103 variety were resistant to all races, except IB-45 race, which were susceptible. While, the two Egyptian varieties, Sakha 101 and Sakha 104 were susceptible to blast of the five races. For monogenic rice genotypes, results showed that IRBLKS-S, IRBL3-CP4 and IRBL5-M which carried (Pik-s, Pi3 and Pi5) blast resistance genes were resistant to all races, except EG-5 race, which were susceptible and the other rice monogenic line IRBL7-M which carry Pi7(t) was resistant against IG-1, 367 and 374 races and susceptible under EG-5 and IB-45 races of M. grisea. The results also suggested that the six major genes; Pi-i, Pi-sh, Pik-s, Pi3, Pi5, Pi7 (t) were effective under Egyptian conditions and can be used for improving blast resistance character in breeding program. The results of the inheritance of blast resistance using sixteen F1 and F2 rice populations showed that all F1s were resistant to blast. Among the F2 segregating generation eight populations showed resistant and non-segregation ratio, four rice crosses gave segregations 15 resistant (R) : 1 susceptible (S), while the segregating ratio of another four crosses were 3 R : 1 S for blast. In addition, the analysis of variance revealed significant differences among genotypes, lines, testers and line x tester interactions for blast reaction, duration, plant height, panicle length and weight, flag leaf area, number of panicles/plant and primary branches/panicle, 1000-grain weight and spikelet fertility % traits, indicated that the genotypes had wide genetic diversity for the studied traits. However, significant differences due to interactions of line x tester for the above mentioned traits, indicating the importance of both additive and non-additive gene action in the inheritance of these traits. Highly significant and desirable heterosis and heterobeltiosis were recorded in Sakha 103 X IRBL5-M for improving blast resistance, plant height, flag leaf area, number of panicles/plant and spikelet fertility %. In addition, Sakha 102 X IRBLKS-S rice hybrid was the best cross combinations for early maturity, shortness, area of flag leaf, number of panicles/plant and 1000-grain weight traits and it could be used in breeding program to improving these characters in rice

GENETIC DIVERGENCE ANALYSIS IN HRDC RICE (Oryza sativa L.) HYBRIDS IN BANGLADESH

Genetic divergence of 48 IRRI developed F1 rice hybrids were studied through Mahalanobis D2 and principal component analysis for ten characters in Gazipur and Pabna district during dry season 2012-13. Among 48 genotypes, cluster analysis resulted in five clusters following Ward’s method. During dry season for both regions, cluster I incorporated the highest number of genotypes. Significant differences among the genotypes but non-significant differences among replications were noticed for most of the parameters under study. The inter-cluster distance was larger than intra-cluster distance suggesting wider diversity among the genotypes. In Gazipur, the maximum inter-cluster D2 value was recorded between cluster III and V (6.69) and the minimum between cluster II and IV (0.69). The intra-cluster distance was maximum in cluster IV (3.60) and minimum in cluster I (0.33). In Pabna, maximum inter-cluster distance was exhibited between cluster IV and II (16.43) but minimum between cluster II and III (3.98). Maximum intra-cluster distance (4.40) was recorded in cluster IV whereas minimum in cluster I (0.83). Based on positive value of vector 1 and vector 2, panicle number m-2, spikelet fertility (%) and 1000-grain wt. (g) had maximum contribution towards genetic divergence among the characters studied. Cluster means indicated considerable differences in the mean values of different parameters. The highest cluster means for panicle weight (g), spikelet fertility (%), 1000 grain wt. (g) and grain yield (kg ha-1) were derived from cluster IV. Therefore, more prominence should be given to the lines under cluster IV that having genetic potentiality to contribute better for yield maximization of hybrid rice.

Pollen and Spikelet Analysis in F1 Rice Hybrids and their Parents

Pollen analysis can be used to discriminate between different species, identify possible interspecies hybrids, identify restorer and maintainer lines, useful to study genetics of restorer gene, interaction between chromosome and cytoplasm and relationship between parents. Pollen abortion system of male sterility is an important tool in hybrid rice production and spikelet is the major yield components. Nine improved cultivars, six landraces and three wild aborted cytoplasmic-genetic male sterile (CMS) lines were used to analyze pollen and spikelet in F1 rice hybrids and their parents. The frequency of pollen categories and its relationship to spikelet fertility were investigated. Pollen sterility of the F1s was determined by staining pollen grains in 1% potassium iodide-iodine (I-KI) solution. Spikelet fertility was determined by counting the total number of seed set in proportion to the total number of spikelets. Correlation and regression coefficients for some traits were computed. In hybrids, pollen fertility ranged from 0.5 to 82% and spikelet fertility from 0 to 87%. Pollen fertility varied from 28 to 97%, while spikelet fertility from 73 to 91% in pollen parents. The highest and the lowest percentages of pollen fertility were found in Chaite-6 and Chiunde cultivars respectively. Spikelet fertility percentage varied widely among hybrids and many hybrids had lower spikelet fertility percentage than their parents. Therefore, it is of practical importance to understand the causes of high spikelet sterility in hybrids for possible increase in spikelet fertility. Highly significant positive correlation was found between stained round fertile (SRF) pollen and spikelet fertility. The positive value of correlation and regression coefficient on SRF and spikelet fertility were found between F1 and mid parent, and F1 and male parent. High fertility of cross may be due to the presence of a wide compatibility gene or restorer genes in the cultivar. Lower pollen and spikelet fertility of the crosses was attributed to effect of the genetic background of the tester parent. Nepal Agric. Res. J. Vol. 8, 2007, pp. 120-126 DOI: http://dx.doi.org/10.3126/narj.v8i0.11605

Assessment of Genetic Parameters for Yield and Yield Components in Hybrid Rice and Parents

Thirty F1 rice hybrids along with complete set of 13 parents and checks were evaluated for variability, heritability and genetic advance in different yield and yield contributing traits. The data was recorded on five randomly selected plants for fifteen quantitative characters. The treatment, i.e. mean sum of squares due to genotypes showed significant differences for 14 characters studied, indicating the presence of high genetic variability among the genotypes. The estimates of GCV were lower than the respective PCV, indicating the influence of environmental factors on the expression of the traits studied. Characters like percent pollen fertility (99.9, 33.33), grain yield hill-1 (99.2, 31.13), harvest index (98.5, 30.42) and number of filled grains panicle-1 (97.8, 30.04) showed high heritability coupled with moderate genetic advance as percent of mean, suggesting that selection for the improvement of these characters may be rewarding. This also indicates greater role of non-additive gene action in their inheritance suggesting heterosis breeding could be used to improve these traits.

Assessment of Genetic Parameters for Yield and Yield Components in Hybrid Rice and Parents

Thirty F1 rice hybrids along with complete set of 13 parents and checks were evaluated for variability, heritability and genetic advance in different yield and yield contributing traits. The data was recorded on five randomly selected plants for fifteen quantitative characters. The treatment, i.e. mean sum of squares due to genotypes showed significant differences for 14 characters studied, indicating the presence of high genetic variability among the genotypes. The estimates of GCV were lower than the respective PCV, indicating the influence of environmental factors on the expression of the traits studied. Characters like percent pollen fertility (99.9, 33.33), grain yield hill-1 (99.2, 31.13), harvest index (98.5, 30.42) and number of filled grains panicle-1 (97.8, 30.04) showed high heritability coupled with moderate genetic advance as percent of mean, suggesting that selection for the improvement of these characters may be rewarding. This also indicates greater role of non-additive gene action in their inheritance suggesting heterosis breeding could be used to improve these traits.

IDENTIFICATION OF DROUGHT TOLERANT MOLECULAR MARKERS IN RICE (Oryza sativa L.) I- ASSESSMENT OF F1 GENOTYPES UNDER NORMAL AND DROUGHT CONDITION

The present study was carried out at the Experimental Farm of the Rice Research and Training Center (RRTC), Sakha, Kafer EL-Shiekh, Egypt, during three successive rice growing seasons 2010, 2011 and 2012 aiming to establish combiners that may have drought tolerance characters by hybridization between local sensitive and imported tolerant rice cultivars which will be subjected to aggressive Simple Sequence Repeat (SSR) molecular technique. So, eight genotypes namely; Moroberekan, IET1444, Azucena, IRAT170, GZ530-20-10, Giza177, Giza 178 and Sakha101 were chosen for line by tester cross. The hybrid grains were grown in 2011 as F1 and transplanted in a randomized complete block design (RCBD), with three replications, (each F1 cross transplanted between its parents). All the genotypes (eight parents and 15 F1 crosses) were planted under both normal and imposed drought conditions. The obtained results exhibited that, the parents Moroberekan, IET 1444, Giza 178 and Sakha 101 and the F1 crosses involved these parents, in particular the crosses Moroberekan x Giza177 and IET 1444 x Sakha 101 showed the most favorable mean performances values for root, yield and physiological characters, under stress conditions. Moreover, under drought stress, the following F1 crosses; IET 1444 x Giza177, IRAT 17 x Sakha101 show remarkable increase in the mean performance of average panicle length, average number of panicles per plant, average grain yield per plant as well as harvest index. However, insignificant heterotic effects were recorded for average root volume (RV) with the F1 combiner; GZ350-20-10 x Giza178. Neverthless, root to shoot ratio (R:S) did not show insignificant heterosis effects under drought condition. The most desirable crosses under normal and drought stress were; Moroberekan x Giza177, Moroberekan x Sakha101, IET 1444 x Giza178, IET 1444 x Sakha101. Since these crosses maintained the most favorable shoot, root, yield and physiological characters under both normal and drought stress conditions. The vigorous growth of F1 rice hybrids may partially attributed to the development and function of the root system. Also, it was found that F1 hybrid surpassed parents in the total root length, number. of root per plant. As a result, the root system of F1 hybrids was not only greater in volume, but also longer in length. Additionally, root to shoot ratio showed higher values than that of parents. Signficant GCV estimates were recorded for all the studied traits except the parents IET 1444 for average root volume per plant and the parent Giza 178 for root to shoot ratio under normal condition and Giza 177 for average number of roots per plant for number of roots per plant. Also, signficant GCV estimates were recorded for all the studied traits except the parents IRAT 170, Giza 177 and Giza 178 for average relative water content.

Higher Leaf Area Growth Rate Contributes to Greater Vegetative Growth of F1 Rice Hybrids in the Tropics

The early vigor of hybrid rice (Oryza sativa L.) developed in temperate areas has been mainly attributed to its higher tillering rate. The objective of this study is to identify factors that contribute to greater vegetative growth of Fi hybrid rice recently developed in the tropics. We analyzed data from field experiments conducted from 1994 to1997 in both dry and wet seasons at the International Rice Research Institute farm. Each experiment had one to four pairs of comparisons between best hybrids and best conventional varieties. Parameters used for comparison were tillering rate, leaf area growth rate (LAGR), and crop growth rate (CGR) between transplanting (TR) and midtillering (MT) and also between MT and panicle initiation (PI). In most cases, the hybrids exhibited greater CGR than the conventional varieties, either between TR and MT or between MT and PI or both. The difference in CGR was associated with the difference in LAGR between hybrids and conventional varieties. However, the tillering rate of hybrids was significantly lower than or equal to that of conventional varieties. Therefore, the higher LAGR, independent from tillering, contributed to greater CGR of recently developed F1 hybrid rice in the tropics. The difference in LAGR and CGR between hybrids and conventional varietieswas not associated with tillering. The higher LAGR of the Fl hybrids than that of the conventional varieties could be attributed to their thinner leaf blades.

Knockdown, Mortality, and Progeny Production of Lesser Grain Borers (Coleoptera: Bostrichidae) and Rice Weevils (Coleoptera: Curculionidae) Exposed for Short Intervals on Wheat Treated with Cyfluthrin

Adult lesser grain borers, Rhyzopertha dominica (F.), and adult rice weevils, Sitophilus oryzae (L.), were exposed at bimonthly intervals for 2, 4, 8, and 24 h on wheat treated with 0, 1, 2, and 4 ppm cyfluthrin EC, then removed and held for 2 wk on untreated wheat. The percentage of lesser grain borers that were knocked down after they were exposed increased as exposure interval and concentration increased, and was usually >90% at intervals >4 h for 8 mo after the wheat was treated. Mortality after 2 wk on untreated wheat generally decreased as residues aged, with no difference in mortality among exposure intervals. F1 production of lesser grain borers was low in untreated controls, so effect of exposure could not be determined. The percentage of rice weevils that were knocked down after exposure also increased as exposure interval and concentration increased; however, except for month 0, mortality after 2 wk on untreated wheat was usually <25% for all bioassays on wheat treated with 1 and 2 ppm cyfluthrin. Although the number of F1 rice weevils was dependent on initial exposure interval and concentration, the exposure intervals were not sufficient to prevent oviposition. Progeny production also increased as the residues aged. Results of this study indicate that lesser grain borers and rice weevils will survive if exposed for 24 h or less on wheat treated with cyfluthrin EC.

Evaluation of the Heterosis on Leaf Photosynthesis of Remote‐Cross F1 Rice (Oryza saliva L.)

AbstractThe heterosis of leaf photosynthesis was studied on the main characters included in the range from CO2exchange rate (CER) to enzymatic activity using a remote cross F, rice. The CER was significantly higher than those of the parental strains, showing a 111 % heterosis effect on average; at the same time strong heterosis was observed for the leaf area production and growth. Also stomatal and mesophyll conductances increased in the F1 rice, which may contribute to the increase in CER. Chlorophyll content (Ch1), soluble protein content (SPC) and ribulose 1,5‐bisphosphate (RuBP) carboxylase activity (RCA) were measured as the internal factors related to photosynthesis, and compared between the F1, rice and the parents. For all these factors, the F1 rice showed low values compared to the parents. Positive heterosis was not expressed here. On the other hand, the specific activity of RCA (RCA/SPC) increased in the F1, rice, showing a 120% heterosis effect. This may be regarded as one of the main causes for the increase in CER of the F1, rice. High CER expressed as heterosis concurrently with large leaf area production is one of the important findings in our study, and this may suggest a high possibility of further improvement in biomass production or yield of rice by gathering the advantageous elements into a hybrid plant.

Cyfluthrin Applied with and without Piperonyl Butoxide and Piperonyl Butoxide Plus Chlorpyrifos-Methyl for Protection of Stored Wheat

Soft red winter wheat treated with 0.5, 1.0, 1.5, or 2.0 ppm cyfluthrin, all rates + 8.0 ppm piperonyl butoxide, and all rates with piperonyl butoxide + 6.0 ppm chlorpyrifos-methyl was stored for 10 mo at ambient conditions in southern Georgia. Samples of wheat were bioassayed with lesser grain borer, Rhyzopertha dominica (F.), and rice weevil, Sitophilus oryzae (L.), every 2 mo. Lesser grain borer survival on wheat treated with cyfluthrin alone ranged from 0-37.0%, whereas survival in the cyfluthrin + piperonyl butoxide and cyfluthrin + piperonyl butoxide + chlorpyrifos-methyl combinations ranged from 0 to 16.0%. No F1 adults or ground flour (dockage) was present in incubated samples. Rice weevil survival on wheat treated with 0.5 and 1.0 ppm cyfluthrin steadily increased to a maximum of 94.5 and 43.5%, respectively, after 10 mo. Survival was reduced on wheat treated with 1.5 and 2.0 ppm cyfluthrin, and beetles did not survive in the piperonyl butoxide-chlorpyrifos-methyl combinations. The number of F1 rice weevils and the amount of dockage were greatest in the two lowest rates of cyfluthrin. F1 adults and dockage weight were positively correlated with initial.