Single-plant Plots Research Articles

The Effect of K-Fertilization and Irrigation on the Composition of Cultivated Soils: Examples from Israel

Evaluation of soil sustainability should take into account chemical and mineralogical changes due to cultivation. Potassium (K) application is a key farming practice that may potentially affect phyllosilicate composition and soil properties. Irrigation is another agent that affects soil composition. This study aims to evaluate the imprints of cultivation on the chemical and mineralogical compositions of lowland soils under semi-arid and Mediterranean climate regimes and to assess them with the natural pedogenesis. The sites examined include two permanent plot experiments with crop rotation, and three single-plant plots. Cultivated, control, and fallow soils were analyzed for their chemical and mineralogical composition. The X-ray diffraction patterns of the clay fraction were decomposed to achieve quantitative detection of changes among the illite–smectite (IS) phases and in kaolinite amounts. In loamy and clayey soils dominated by IS phases, cultivation caused minor changes and diverse behavior of the IS phases. Yet, the K balance was negative under high fertilization levels and higher plant mass production. Fertilization enhanced the natural process of transforming IS into kaolinite and illite in the sandy soil, leading to a positive K balance. This study emphasizes the importance of IS minerals as a dynamic K pool that responds to plant needs.

Phenotypic diversity and heritability in Eragrostis tef under irrigated Mediterranean conditions

Tef (Eragrostis tef (Zucc.) Trotter) is a C4 annual cereal, common in Ethiopia, where it was presumably domesticated. Worldwide interest in tef cultivation and consumption has considerably increased in the last few decades because it is a gluten-free grain with high nutritional value. Here we report on the genetic diversity and heritability in a tef germplasm collection characterized in Israel. A total of 408 accessions of tef held in the Israel Gene Bank were grown in 2015 under common garden (screen-house) conditions for propagation and initial phenotyping. A diversity panel, consisting of 273 accessions representing the entire collection's range of phenotypic diversity, was assembled and evaluated in small field plots in 2016. Further evaluation was conducted in 2017, in single-plant field plots (to eliminate admixtures). A representative plant (plot) was selected from each accession grown in 2017 and its single seed descent progenies where grown in 2018 in single-plant plots. The collection exhibited a wide diversity for each of the measured phenotypic traits, across all four environments. High grain yield was associated in most cases with early flowering time, whereas higher biomass was associated with late flowering. Heritability estimates, calculated based on the 2017, 2018 data, varied between 0.11 for plant biomass and 0.75 for 1000 grain weight. This study shows that tef can successfully grow and produce under irrigated Mediterranean conditions. The wide diversity available in our germplasm collection can provide the foundations for breeding new tef cultivars that are better adapted to these conditions.

Dialelo parcial entre clones de Eucalyptus camaldulensis e clones de E. urophylla, E. grandis e E. saligna

O objetivo deste trabalho foi identificar combinações híbridas superiores nos cruzamentos entre clones-elite de Eucalyptus grandis, E. urophylla e E. saligna com clones-elite de E. camaldulensis da Aracruz Celulose S.A., por meio de cruzamentos dialélicos parciais. Para isso, as 44 combinações híbridas obtidas e mais quatro testemunhas foram plantadas de setembro a outubro de 2001, em três localidades: Aracruz, ES; São Mateus, ES; e Caravelas, BA, no delineamento de blocos casualizados com 40 repetições e uma planta por parcela. Dois anos após o plantio, foram avaliadas a circunferência à altura do peito (CAP) e a densidade básica da madeira (DEN). Os dados médios foram submetidos à análise dialélica segundo o método de Griffing (1956), adaptado por Geraldi e Miranda Filho (1988). Constatou-se que muitos híbridos foram promissores tanto para a obtenção de ganhos em CAP quanto para obter a densidade da madeira, pois associaram média e variância altas. A maior parte da variação entre os híbridos foi explicada pela capacidade geral de combinação, indicando a predominância de efeitos aditivos no controle dos caracteres.

Potencial de híbridos entre clones-elite de eucalipto por meio de marcadores microssatélites

O objetivo deste trabalho foi avaliar o potencial dos marcadores microssatélites em predizer o comportamento dos híbridos entre clones-elite de eucalipto da empresa Aracruz Celulose. Foram utilizados 21 clones-elite, cruzados conforme o esquema de dialelo balanceado. Os 137 híbridos obtidos, além dos 21 pais e 11 híbridos repetidos, foram avaliados em três locais: Aracruz, São Mateus e Caravelas, em delineamento de blocos incompletos 13x13 com 40 repetições. As parcelas foram constituídas de uma planta, espaçadas 3x3 m. Os caracteres circunferência à altura do peito (CAP) e densidade básica da madeira foram avaliados aos dois anos de idade. Os dados foram submetidos à análise dialélica e, posteriormente, foi obtida a correlação entre a divergência genética dos genitores, obtida por meio dos marcadores microssatélites, e as estimativas dos parâmetros do dialelo. A divergência genética apresentou coeficientes de correlação significativos apenas com a capacidade específica de combinação para CAP e com a média dos híbridos para CAP. A predição por meio de marcadores microssatélites possui baixa precisão para poder ser utilizada em substituição aos cruzamentos dialélicos.

Combining ability of elite clones of Eucalyptus grandis and Eucalyptus urophylla with Eucalyptus globulus

In Brazil, eucalyptus breeding programs for cellulose production has used two species, Eucalyptus grandis and Eucalyptus urophylla. Nevertheless, it would be useful to introgress alleles from other species to improve wood quality and volume. The objective of this research was to evaluate the hybrid potential of elite clones of E. grandis and E. urophylla from the Aracruz Celulose Company S. A. with Eucalyptus globulus clones. To do so, six elite clones were crossed with ten E. globulus clones in a half-diallel mating design. The resulting hybrid combinations as well as the four check clones were evaluated in randomized complete block experiments with single plant plots and 40 replicates from September to October 2001 at three Brazilian sites, Aracruz and Sao Mateus in the Espirito Santo state and Caravelas in Bahia State. Two years later the circumference at breast height (CBH) and the wood density (WD) were measured. The means were submitted to diallel analysis according to the Griffing method (1956), adapted by Geraldi and Miranda Filho (1988). Although the number of clones involved was small, the crossings of elite clones of E. grandis and E. urophylla with clones of E. globulus were promising, especially for wood quality gains.

(374) Fertilization of Southern Highbush Blueberries on Pine Bark Beds

Bearing `Misty' and `Star' southern highbush blueberries were grown on pine bark beds and fertilized at three rates using granular and liquid fertilizers with a 3–1–2 (1N–0.83K–0.88P) ratio. Granular fertilizer was applied 8 times per year at 4-week intervals beginning in April and continuing through October. Liquid fertilizer was applied with low volume irrigation 16 times per year at 2-week intervals during the same period. During the growing season, irrigation was applied at 2- to 3-day intervals in the absence of rain. A 2 cultivar × 2 fertilizer type × 3 fertilizer rate factorial arrangement of treatments was replicated 8 times in a randomized complete-block design. All fruits were harvested from single-plant plots at 3- to 4-day intervals. Canopy volume was not affected by fertilizer type, but fruit yield was slightly greater for granular than for liquid fertilizer treatments. In 2003, fruit yield of 2.5-year-old `Misty' and `Star' plants increased with increasing fertilizer rates up to the highest rate tested (50 g N/plant/year). Similarly, in 2004, fruit yields increased with increasing fertilizer rates up to the highest rate (81 g N/plant/year). Root distribution was limited to the 12-cm-deep layer of pine bark with very few roots penetrating into the underlying soil. The positive growth responses of blueberry plants to high fertilizer rates in pine bark beds suggests that soluble fertilizer was leached through the pine bark layer into the soil below the root zone. More frequent, lighter applications of soluble fertilizers, use of slow-release or controlled-release fertilizers, and careful irrigation management may improve fertilizer use efficiency of blueberry plantings on pine bark beds.

Spatial dependence and block designs in spaced plant herbage trials

Data from three ryegrass spaced plant variety trials conducted at Crossnacreevy, Co. Down in each of 1989, 1990 and 1991 were investigated for evidence of spatial dependence. Spatial dependence was most evident in variates measuring the overall dimensions of the plants, especially late season variates. However, the ‘date of ear emergence’ variate, which identifies most of the variety distinctnesses that the trials are intended to detect, was not spatially dependent. On average, 45% of the residual variation in the plot means of the spatially dependent variates was estimated to be of a spatial nature. Consequently, it is likely that the efficiency of analysis of these variates would be improved by using spatial analysis instead of non-spatial analysis or by using alpha (incomplete block) designs instead of complete block designs. The spatial information was used to determine the optimal incomplete block sizes and the likely increase in efficiency due to using alpha designs instead of complete block designs. The optimal incomplete block size for a trial with 10 plants per plot was compared with the optimal incomplete block size for the same trial with single plant plots at the same spacing and was found to be smaller. The gains in efficiency were larger in the trial with 10 plants per plot than in the trial with single plant plots.

Peach and Nectarine Scion Influence Suckering of Nemaguard Rootstock

The randomized complete-block design was a split plot with main plots being the 50 scion/ rootstock combinations (single-plant plots), replicated in 20 blocks and with year as subplots. For analysis of variance, sucker count data were transformed into the square root of the number of suckers plus 0.5 (Gomez and Gomez, 1984). Mean separation of scion treatment means was performed with a cluster analysis technique (Gates and Bilbro, 1978). A peach [Prunus persica (L.) Batsch] scion cultivar that enhanced rootstock suckering might be useful for revealing the suckering tendencies of test rootstocks. This paper reports the scion genotype influence on suckering by Nemaguard rootstock. Forty-nine scion cultivars were budded in 1986 by a commercial nursery onto openpollinated Nemaguard seedlings. Virus-free

Assessing the resistance to gangrene of progenies of potato (Solanum tuberosum L.) from parents differing in susceptibility

The resistance to gangrene (caused byPhoma exigua var.foveata) of progenies from two hybridisation schedules involving cultivars resistant, susceptible, or of intermediate reaction to gangrene was assessed. Two methods of sampling tubers from field-grown single-plant plots of 18 clones representing each progeny were used: one tuber was taken from each plant, and a bulk sample of 18 tubers was selected at random from the whole progeny. Gangrene resistance was assessed after incubating tubers which had been rolled in cornmeal-sand inoculum ofP. exigua var.foveata, and was expressed as a percentage of tubers infected. Results from the two methods of sampling correlated closely, and agreed well with tests in a subsequent year on 10-tuber samples of each individual clone.

A comparison between single plant plots and five plant plots for the initial selection stage of a potato breeding programme

The efficiency of single plant selection in the initial selection stage of a potato breeding programme was examined. A random sample of potato clones was grown in single plant plots and also in tworeplicates of five plant plots. After harvest, each plot was visually assessed by three potato breeders; total tuber weight and number of tubers per plant were also recorded, from which mean tuber weight was calculated. The error variances of the single plant plots were found to be significantly greater than from the five plant plots for total tuber weight, mean tuber weight and number of tubers per plant, but not significantly different for breeders' preference. Coefficients of correlation between single and five plants plots were significantly greater than zero for all traits examined, but they were lower than the corresponding correlations between the two replicates of five plant plots. Although a random sample of clones was examined, each clone had been assessed for breeders' preference the previous year. When the clones were grouped according to the previous years preference scores, it was found that the correlation coefficients between single and five plant plots for breeders' preference were inversely related, in magnitude, to the mean preference score of each group. It was concluded that single plant selection was generally ineffective, particularly when only the ‘better’ clones, from the previous years assessment, are examined.

Arborvitae, A. Cupressella Control Berkeley, California, 1974-75

Abstract Established landscape planting of arborvitae shrubs, 4 to 7 feet in height, were sprayed with hand compression sprayers to point of complete coverage on April 12, 1974. Single plant plots were used with 4 replications of all treatments in a randomized complete block design. Adult moths were in flight on date of application. On March 14, 1975, 5 foliage tips were cut from each plot, weighed, and cocoons counted prior to emergence of 1975 generation of moths. On that date also, unsightliness ratings given to all plots based on rating of 1 to 10; represented no visible injury and 10 represented extreme browning.

Pyracantha L. Kunoensis Control Walnut Creek, California, 1973-74

Abstract Park planting of pyracantha shrubs, 6 to 8 feet in height, were sprayed with compression sprayers to point of runoff in spring-summer of 1973. Peak of crawler emergence occurred about June 1. Single plant plots were used with 4 replications of all treatments in a randomized complete block design. On May 27, 1974, 5 twig samples, each about 11 inches long, were cut from each plot and females of the 1973 generation which survived the treatments were counted.

Intra-varietal variability and response to single plant selection inGossypium hirsutumL.: II. Genotypic variability

SummaryProgenies of randomly chosen plants from spaced plant populations of four American and one African variety ofGossypium hirsutumL. were grown in replicated single-plant plots at Kimberley Research Station in 1967–68 (all varieties) and 1968–9 (two varieties only) to estimate intra-varietal parameters of genetic variability.Estimates of broad-sense heritability were usually similar when derived from components of variance on either a one- or two-season analysis basis or by parentprogeny regression Heritabilities were in general lowest for lint yield and boll number and highest for lint percentage. Mean value of heritability for lint yield and boll number, considered consistent enough on a varietal and seasonal basis to allow averaging, was about 0·15. Components of variance estimates of heritability on a single environment basis for other attributes ranged as follows: boll weight from 0·05 to 0·56, lint percentage from 0·29 to 0·80, mature height from 0·00 to 0·51, micronaire value from 0·20 to 0·63 and Pressley strength index from 0·05 to 0·56.Genetic coefficients of variation showed an opposite trend to that for heritability: lint yield and boll-number values were large and lint percentage, micronaire value, and Pressley strength indices small. Expected responses to selection for the top 2·5 % of the population for lint yield and boll number at around 10% were usually higher than for other attributes.Genotypic and phenotypic correlations were mostly similar but correlations often deviated widely between varieties. Positive lint yield correlations with micronaire value and negative lint yield correlations with Pressley strength index were recorded; these are often undesirable associations for breeding.The association between the period of maintenance under Ord conditions and variability shown phenotypically in the original populations was not evident from the quantitative inheritance studies. Residual variability following breeding was considered as accounting for the larger portion of the genetic variability.