Association mapping reveals loci associated with multiple traits that affect grain yield and adaptation in soft winter wheat     

Dennis N. Lozada  R. Esten Mason  Md Ali Babar  Brett F. Carver  Gina-Brown Guedira  Keith Merrill  Maria Nelly Arguello  Andrea Acuna  Lucas Vieira  Amanda Holder  Christopher Addison  David E. Moon  Randal G. Miller  Susanne Dreisigacker 《Euphytica》2017,213(9):222

Genome-wide association studies (GWAS) are useful to facilitate crop improvement via enhanced knowledge of marker-trait associations (MTA). A GWAS for grain yield (GY), yield components, and agronomic traits was conducted using a diverse panel of 239 soft red winter wheat (Triticum aestivum) genotypes evaluated across two growing seasons and eight site-years. Analysis of variance showed significant environment, genotype, and genotype-by-environment effects for GY and yield components. Narrow sense heritability of GY (h ²  = 0.48) was moderate compared to other traits including plant height (h ²  = 0.81) and kernel weight (h ²  = 0.77). There were 112 significant MTA (p < 0.0005) detected for eight measured traits using compressed mixed linear models and 5715 single nucleotide polymorphism markers. MTA for GY and agronomic traits coincided with previously reported QTL for winter and spring wheat. Highly significant MTA for GY showed an overall negative allelic effect for the minor allele, indicating selection against these alleles by breeders. Markers associated with multiple traits observed on chromosomes 1A, 2D, 3B, and 4B with positive minor effects serve as potential targets for marker assisted breeding to select for improvement of GY and related traits. Following marker validation, these multi-trait loci have the potential to be utilized for MAS to improve GY and adaptation of soft red winter wheat.  相似文献   

Host status of cover crops for root-lesion nematodes (Pratylenchus spp.) associated with apple orchards in South Africa     

Knoetze  Rinus  Addison  Matthew  De Waele  Dirk 《植物病害和植物保护杂志》2023,130(1):105-113

Journal of Plant Diseases and Protection - The host response of 17 cover crop cultivars to infection by single-species populations of Pratylenchus hippeastri, Pratylenchus vulnus and Pratylenchus...  相似文献   

NOCTURNAL ACTIVITY OF BIRDS ON SHRIMP MARICULTURE PONDS     

Jeffrey L. Beynon  David L. Hutchins  Anthony J. Rubino  Addison L. Lawrence  Brian R. Chapman 《Journal of the World Aquaculture Society》1981,12(2):63-70

Birds can reduce production of shrimp in mariculture grow-out ponds through predation and competition for feed. This study involved weekly nocturnal enumeration of bird populations and observation of nocturnal avian habits on a series of 0.1 ha experimental ponds at the Texas A&M University Shrimp Mariculture Facility at Corpus Christi, Texas. Observations were conducted hourly from sunset to sunrise during October through December 1980. The rate of predation was evaluated every three hours by comparing the number of feeding attempts to the number of successful prey captures over a known time period. Gulls (Family Laridae) acted primarily as competitors for feed. Active feeding by gulls was restricted to daylight hours, consequently feed loss decreased when the feed was distributed at or after dusk. Major preadatory birds included herons and egrets (F. Ardeidae), migratory ducks (F. Anatidae), and, to a lesser extent, grebes (F. Podicipedidae) and shorebirds (Order Charadriiformes). Bird predation decreased pond production by 75% in some ponds.  相似文献   

Indigenous management of tropical forest ecosystems: the case of the Kayapó indians of the Brazilian Amazon   总被引：1，自引：0，他引：1  

Darrell Addison Posey 《Agroforestry Systems》1985,3(2):139-158

The Kayapó Indians of Brazil's Amazon Basin are described as effective managers of tropical forest, utilizing an extensive inventory of useful native plants that are concentrated by human activity in special forest areas (resource islands, forest fields, forest openings, tuber gardens, agricultural plots, old fields, and trailsides). Long-term transplanting and selection of plants suggest semi-domestication of many species. The overall management strategies of forest also includes many manipulated animal species (birds, fish, bees, mammals) utilized as food and game. Forest patches (apêtê) are created by Indians from campo/cerrado using planting zones made from termite and ant nests mixed with mulch: formation and development of these is briefly discussed, including the implications for new ideas concerning reforestation and campo management. Finally an integrative cognitive model is presented showing the relationships between variants of forest and savanna recognized by the Kayapó. Indigenous knowledge of subtle similarities between conceptually distinct ecological units in the model allows for the interchange of botanical material between microclimates to increase biological diversity in managed areas. It is suggested that indigenous knowledge is extremely important in developing new strategies for forest and campo/cerrado conservation, while improving productiveness of these ecological systems. Such knowledge is not only applicable for Amazônian Indians, but also has far-reaching implications for human populations throughout the humid tropics.This is a preliminary survey of indigenous management strategies that is generated as a part of the Projeto Kayapó , an interdisciplinary ethnobiological research project funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brazilian National Council for Scientific and Technological Development) and the World Wildlife Fund. I would like to thank Drs. Gerhard Gottsberger and Anthony Anderson for their assistance in collecting plants that are currently being identified to supply more complete data on Kayapó subsistence. I also wish to thank FUNAI (Fundaão Nacional do Índio) for their assistance and support, as well as FAB (Fora Aérea Brasileira) and VOTEC for providing some transportation to/from Gorotire, and the Unevangelized Field Missions for their assistance in providing communication and acquiring supplies.  相似文献   

Dietary Effects on Sperm Quality of Litopenaeus vannamei Broodstock   总被引：1，自引：0，他引：1  

Martin  Perez-Velazquez Mayra L.  Gonzáez-Félix Addison L.  Lawrence William A.  Bray Delbert M.  Gatlin  III 《Journal of the World Aquaculture Society》2003,34(1):92-98

A 56‐d feeding trial was conducted to investigate the effect of diet on sperm quality of Pacific white shrimp Litopenaeus vannamei broodstock. Dietary treatments consisted of a combination of 75% dry maturation diet and 25% fresh‐frozen squid (dry‐weight basis). Supplemental nutrients of the maturation diet were selectively deleted and replaced with wheat starch to produce the following treatments: 1) 75% basal maturation diet plus 25% squid (control); 2) 75% maturation diet without supplemental vitamins plus 25% squid; 3) 75% maturation diet without supplemental cholesterol and phospholipids plus 25% squid; 4) 75% maturation diet without supplemental astaxanthin plus 25% squid; and 5) a fresh diet composed of 60% squid and 40% Maine bloodworms. Shrimp fed the control diet and the diet without supplemental astaxanthin had significantly higher mean (± SEM) change in sperm count (4.6 ± 3.2 million sperm cells and 2.9 ± 2.5 million sperm cells, respectively), with respect to baseline (8.7 ± 1.0, 6.4 ± 1.0, 9.0 ± 1.3, 6.6 ± 0.7, and 6.0 ± 0.8 million sperm cells for treatments 1, 2, 3, 4, and 5, respectively), than shrimp fed the diet without supplemental vitamins (‐1.7 ± 2.6 million sperm cells), but not significantly higher than those of shrimp receiving the diets without supplemental cholesterol‐phospholipids (1.2 ± 2.5 million sperm cells) and the fresh diet (1.3 ± 1.6 million sperm cells). Dietary deficiencies also were reflected in weight gain of shrimp fed the diet without supplemental vitamins (‐2.0 g) and the fresh diet (‐0.8 g). which were significantly lower than weight gain of shrimp fed the control diet (1.1 g) and the diet without supplemental cholesterol‐phospholipids (0.8 g). No significant differences were detected among treatments for percentage of abnormal sperm and survival data. Results demonstrated a significant effect of diet on reproductive quality of male L. vannamei and indicated that the typical combination of fresh‐food organisms used is not nutritionally optimal for male broodstock.  相似文献   

Preliminary evaluation of a purified nucleotide mixture as a dietary supplement for Pacific white shrimp Litopenaeus vannamei (Boone)   总被引：2，自引：0，他引：2  

Peng Li  Addison L Lawrence  Frank L Castille  & Delbert M Gatlin III 《Aquaculture Research》2007,38(8):887-890

  相似文献   

Digestive Characteristics of the Sea-Urchin Lytechinus variegatus (Lamarck) (Echinodermata: Echinoidea) Fed Prepared Feeds   总被引：1，自引：0，他引：1  

Thomas S.  Klinger John M.  Lawrence Addison L.  Lawrence 《Journal of the World Aquaculture Society》1994,25(4):489-496

Lytechinus variegatus were fed two prepared feeds identical in composition except one contained only soybean protein and the other contained equal concentrations of fish and soybean protein. Feeding rate, defecation rate, passage time through the gut, apparent dry matter digestibility of protein and carbohydrate, and the production of gut tissue did not differ significantly ( P > 0.05) with feed type. Individuals about 50 mm in diameter and 60% wet body-weight consumed about 3-g wet weight of feed per day. Feeding rate decreased during the experiment, but defecation rate did not. The throughput rate was two days with considerable mixing of feed in the gut. Fecal production ceased two days after cessation of feeding. Only trace amounts of feed remained in the gut three days after feed was not available. The apparent dry matter digestibility was 62% for soluble protein and 35% for soluble carbohydrate for both feeds. The apparent dry matter digestibility of ash was 19% for the feed with soybean meal alone, and 11% for soybean and fish meal. The apparent dry matter digestibility calculated by the use of chromic oxide is greater than that calculated by the use of ash.  相似文献   

Practical Molt Staging of Penaeus setiferus and Penaeus stylirostris   总被引：1，自引：0，他引：1  

Lori  Robertson  William  Bray  Joanna  Leung-Trujillo  Addison  Lawrence 《Journal of the World Aquaculture Society》1987,18(3):180-185

Molt staging has many applications in penaeid aquaculture as a routine procedure. Using criteria developed for various crustaceans, a method of rapid molt staging was applied to Penaeus stylirostris and Penaeus setiferus adults. The most useful characters were the degree of epidermal retraction from the setal bases and epidermal retraction from the cuticle coupled with the development of new setae. The duration of the molt cycle of P. stylirostris was 11.5 ± 1.0 days ( N = 5) at 27–29 C. The early postmolt, late postmolt, intermolt, early premolt and late premolt stages were readily determined. For P. stylirostris , the duration of postmolt was 27% of the cycle; intermolt, 17%; and premolt, 56%. The length of the molt cycle of P. setiferus at 27–29 C was 13.6 ± 1.0 days ( N = 21) with postmolt occupying 22% of the cycle; intermolt, 19%; and premolt, 59%. Unilaterally eyestalk enucleated P. setiferus had a significantly shorter molt cycle than intact P. setiferus (11.7 ± 1.21 days vs. 13.6 ± 1.02 days, P < 0.05). There were no differences in molt cycle duration between the sexes, whether enucleated or intact ( P > 0.05). A series of illustrations identifies the key characteristics for determining stage of molt in these penaeids.  相似文献   

Spermatophore Generation Times in Penaeus setiferus, P. vannamei, and P. stylirostris   总被引：1，自引：0，他引：1  

Joanna R.  Leung-Trujillo Addison L.  Lawrence 《Journal of the World Aquaculture Society》1991,22(4):244-251

Spermatophore development times were studied in three species of penaeid shrimp, Penueus setifcrus, P. vannumei , and P. stylirosrris . In the terminal ampoule, the progression of spermatophore formation occurred in 4 stages (I-IV). The duration of each stage varied with species and ablation state. In unablated males, with spermatophores manually or electrically removed, structnrally complete spermatophores containing high numbers of morphologically normal sperm were formed in 2–4 days for P. vannamei , 4–6 days for P. stylirostris and 5–7 days for P. setiferus . Unilateral eyestalk ablation of P. setiferus accelerated spermatophore production time by approximately 2 days, and significantly increased spermatophore weight and sperm count without affecting sperm quality.
Spermatophore removal techniques had little effect on development time in P. vannamei . However, in P. setiferus , new spermatophores were produced faster in males mating naturally than in those males whose spermatophores were removed electrically.  相似文献   

The Effect of Controlled Soil Sulfur Concentration on Growth and Survival of Litopenaeus vannamei     

Gad  Ritvo Joe B.  Dixon William H.  Neill Tzachi M.  Samocha Addison L.  Lawrence 《Journal of the World Aquaculture Society》2000,31(3):381-389

Abstract.— In a microcosm study, sodium sulfate was mixed with a controlled composition soil to yield sulfur concentrations of 100 to 3,000 mg/kg and the mixture was inundated to a depth of 35 cm with 18-ppt salinity water. One juvenile Litopenaeus vannamei with initial weight averaging 0.3 g was placed in each soil-water microcosm and fed for 96 d. Dissolved oxygen concentration was maintained at approximately 70% air saturation. Calculated interstitial hydrogen sulfide concentration 0.5 cm below the soil-water interface increased with time, reaching maximum values ranging from 57 to 113 mg/L. Interstitial sulfide concentrations 0.5 cm below the soil-water interface increased as a function of soil S. Average weight gain of shrimp ranged from 7.4 to 8.7 g across treatment groups. Differences in shrimp weight gain and survival among treatments were not significant. A higher dissolved oxygen demand due to sulfide oxidation implies greater risk of shrimp mortality if the soil-water boundary is disturbed. Further, this study suggests that shrimp growth is not adversely affected by high soil sulfide concentration provided the sediment surface remains oxidized and that dissolved oxygen concentration in the overlying water is maintained at 70% saturation.  相似文献