CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Genetic evaluation for understanding combining ability effects and Heterotic grouping in Maize (Zea mays L.)
Full text linkCombining ability of the genotypes/lines is a major factor in planning the breeding programme and for development of Heterotic hybrids. In the present study, twenty maize inbred lines were crossed to three diverse testers CM-111, GPM-549 and GPM-581 and the resultant F1 hybrids were evaluated in an alpha lattice design. General combining ability of lines which is representation of additive gene action was found to be significant for all the quantitative traits. Specific combining ability which is indication of non-additive gene action was found to be significant for the traits number of kernel rows per cob, number of kernels per row, cob girth, cob length, test weight and grain yield. Lines VL-058725, VL-1018527 and VL-108723 produced heterotic hybrids in cross combination with any of the tester due to their high GCA effects. Whereas, the lines VL-0536, SNL-1574 and VL-109086 interacted positively with their testers thus producing heterotic hybrids with high positive SCA. GGE biplot analysis was helpful in visualizing the combining ability effects and identify heterotic pattern among theinbred lines. Heterotic grouping based on SCA and mean grain yield was able to classify thirteen of the twenty inbred lines into two distinct heterotic groups i.e., Heterotic group A and B consisting of six and seven lines respectively. Heterotic group A consisted of lines with high GCA whereas, heterotic group B with low GCA lines. SCA effect showed significant positive correlation with all the quantitative traits and played a prominent role in determining the performance of hybrids, thus indicating the importance of non-additive gene action in developingheterotic hybrids
Whole tree system evaluation of thinning a pine plantation in southern Italy
Full text linkIn Italy, some silvicultural treatment as thinning could be carried out in an economic way adopting systems based on small-scale mechanization. This paper examines the productivity standards of wood biomass in coniferous plantation thinning in Southern Italy under the conditions of small-scale forestry. The objectives of the study were to evaluate the incidence of different silvicultural treatments on productivity and harvesting costs and create productivity models for typical harvesting system used for wood thinned from Calabrian pine. Three different sites were monitored on the Sila Massif forest, and the experimental plan included three area tests, subjected in the last thirty years to intermediate cuttings with different thinning grade: light thinning (A thesis), moderate thinning (B thesis), heavy thinning (C thesis). The authors developed a productivity model for motor-manual felling and skidding timber with wheeled farm tractors, equipped with winch using a time motion study. Whole tree extraction system in coniferous plantation applied with typical felling system traditional has guaranteed productivity standards at a reasonable cost reducing high operational cost per unit harvested. The results, therefore, underlined that it economic possible to wood biomass harvest relatively small-diameter from thinning stands favoring moderate and heavy thinning
Evaluation of different wood harvesting systems in typical Mediterranean small-scale forests: a Southern Italian case study
Full text linkUse of small-scale harvesting equipment in forestry is increasing in many regions of the world and tractor-based systemsare the most common type of small-scale forestry equipment. This equipment is smaller, less expensive and less productivethan advanced forestry machines and the choice of method depends on forest site-specific conditions. In southern Italy the prevailingconditions are those characteristic of small-scale forestry: harvested areas and volume are limited and ground-based extraction isstill the most common harvesting technique. Two harvesting systems conventionally adopted in Italian small-scale forestry are thoseusing either winch or grapple fitted farm tractors for wood extraction. A continuous time study was adopted to determine productivityrates and wood extraction costs and develop skidding time prediction models for these two different wood harvesting systems asused in typical Mediterranean forests, in chestnut and silver fir thinning operations. Comparing winch and grapple extraction revealedconsiderable differences in productivity (2.91 and 5.92 m3 h-1 respectively). Factors significantly affecting productivity differenceswere extraction distance and payload per turn. The study concluded that farm tractors can be used for small scale harvesting operationsand its results can be used to set piece rates, design and rationalize work and estimate costs. In order to sustain small-scaleharvesting equipment effectiveness, skid trails should be planned in forests. The use of farm tractors needs to be encouraged as analternative self-sufficient productivity method in small-scale forestry operations
Comparison among three different testers for the evaluation of new maize inbred lines (Zea mays L.)
Full text linkThis study aimed to evaluate twenty elite yellow maize inbred lines as well as the suitable tester among threedifferent. The elite inbred lines were crossed as female parents with three testers as male parents, i.e.Gem.Pop.(Broad genetic base), Single cross 101(Narrow genetic base) and Inbred line 100 (Narrow genetic base) at theExperiment Research Station of Moshtohor, Benha University, Egypt during 2014 growing summer season. Theresulting 60 top crosses with three commercial check hybrids i.e. SC.155, SC. Pioneer 3080 and TWC.352 wereevaluated in a yield trail in two sowing dates during 2015 growing summer season. Each experiment was laid outin randomized complete block design with three replications. The recommended packages of agronomic practiceswere followed to achieve a good yield. The morphological and agronomical evaluated traits included eardiameter (ED), number of rows per ear (NRE), number of kernels per row (NKR), 100-kernel weight (100KW) andgrain yield per acre (1 hectare= 2.5 acre) (GYPA). The results showed significant mean square for sowing dates forall traits except for (NRE) and (NKR). The parental inbred lines (L-4, L-5, L-10, L-12, L-13, L-14 and L-19) possessedhigh GCA effects for grain yield. The inbred tester resulted the best combiner among the testers and expressedthe best SCA effect over all crosses. Therefore, inbred line or single cross tester is preferred as it may permit quickerutilization of new lines in commercial hybrids especially if the tester is already in commercial use
Evaluation of Maize for Different Methods and Levels of Zinc Application
Full text linkThe different methods of zinc (Zn) application with various doses were studied in maize (Zea mays L.).The methodsadopted namely, seed priming (1, 2 and 3%), seed treatment (2, 4 and 6 g kg-1 seed), soil application (4, 6 and 8kg ha-1) and foliar application (0.25, 0.50 and 0.75%) with three levels of each. Foliar application of Zn at 0.75%has exhibited phytotoxicity initially but later the phytotoxicity disappeared after 8-10 days. Irrespective of theZn application method and level growth, yield, Zn content and quality of maize was significantly enhanced overabsolute control. Seed treatment was found to be the cheapest Zn application method. Seed treatment of Znat 4 g kg-1produced highest maize grain yield, net returns, and the maize grains were enriched with Zn and weresuitable for human consumption as a biofortified Zn source. Maximum residual elemental Zn in soil was found dueto foliar application of Zn at 0.75%. However, seed treatment of Zn at 4 g kg-1resulted suitable for an eco-friendlyand sustainable method of Zn application for agronomic packages and practices
The walnut plantations (Juglans spp.) in Italy and Spain: main factors affecting growth
Full text linkWalnut tree species (Juglans spp.) are commonly used for high-quality wood production in plantation forestry. In this paper, the most relevant walnut plantations in Italy and Spain have been reviewed and analysed under a geographic and technician management point of view. Between 2016 and 2019 a total of 96 plantations (15 - 25 years old) were visited distributed in the North-western part of the Mediterranean basin. A statistical analysis (linear model no interaction and PCA) was then performed to evaluate the relative importance of some environmental and management variables for walnut trees in analysed plantations. Results highlighted a variable situation with many different adopted planting schemes across the regions as well as a not standardised spatial layout and management type (thinning). Lower densities and smaller trees were adopted in Italy with about 200 trees ha-1 versus 330 trees ha-1 in Spain. In addition to the age of the plantation as one of the most influencing parameters also the plantation density and the average crown diameter were highly statistically significant. Overall, the interesting potentiality of walnut for timber production with active management in suitable areas was detected as the focal point for a successful timber production from walnut trees
Clonal effect on rooting and acclimation rates for in-vitro micropropagation in hybrid walnut (Juglans x intermedia Mj 209): preliminary observations
Full text linkThe success of walnut (Juglans sp.) planted forests for timber production have been very variable and genetic material is considered as one of the main drivers (together with site selection and forest management) for the success or failure of the plantations, as the performance of the trees from seed material is very variable. Considering the relevance of this genetic material, several clones have been selected and research have been conducted in order to improve micropropagation procedures. The objective of the present study is to analyze the effects of different clones in the rooting and acclimation rates for in-vitro micropropagation in hybrid walnut (Juglans x intermedia Mj 209). The results show a significative effect of clones on the rooting and the total micropropagation efficiency rates, but not on the acclimation rate. The efficiency rate of D-117 (65%) is considered statistically higher than the one for D-15 (38%), caused by a higher rooting rate of D-117 (73%) compared with D-15 (55%), because acclimation rate (57%) did not show any clone effect. Considering these differences in the micropropagation success, it might be considered (together with other factors) for clone selection to increase the general performance of the plant production units in large-scale propagation
Estimation of crown competition factor for hybrid walnut (Juglans x intermedia) Mj209xRa planted forests in Spain
Full text linkMany walnut (Juglans spp.) planted forests oriented for timber production have been established during the last decades. These plantations usually have a relatively low initial density (250-400 trees ha-1) and 1 or 2 thinnings are needed for valuable timber production (75-150 trees ha-1 for final harvesting). Hence, forest managers need to design when to perform the thinnings and how to do it. Analyzing the trees crown area is a very helpful and easy-to-use tool to evaluate the competence between trees and design the thinnings. The present study proposes two statistical models to estimate Crown Diameter (CD) and Crown Competence Factor (CCF) as a function of Diameter at Breast Height (DBH) for hybrid walnut (Juglans x intermedia) Mj209xRa planted forests, within a DBH range between 5 cm (min) and 33 cm (max). CD and DBH were measured in 702 trees at the Bosques Naturales SA walnut planted forests in Cuenca, Girona and A Coruña (Spain). The CCF model is a tool to evaluate the Crown Competition Factor as a function of measured DBH in a plantation, and, accordingly, decide if a thinning should be done or not yet and design it
Photosynthetic properties of maize hybrids under different environmental conditions probed by the chlorophyll a fluorescence
Full text linkTemperatures and light intensities that deviate from optimum often affect maize (Zea mays L.) production intemperate regions. Objectives of the current study were (i) to investigate the effects of extreme temperaturesand low light conditions on photosynthesis in maize hybrids, (ii) to test whether maize hybrids show distinctivereactions when subjected to different stresses, and (iii) to investigate informativeness of different fluorescenceparameters in different stress conditions. Plants of five maize hybrids were subjected to: cold (Co), low light (LL),heat (H), and severe heat (SH) treatments and field (F) conditions along with control (C), and chlorophyll a fluorescence(ChlF) was measured. ChlF transients were shown to respond to different treatments by changing theappearance of OJIP band, mostly at steps J and I, while the appearance of the K step was confirmed as a goodindicator of temperature stress. PC analysis revealed grouping of parameters with PCs according to their informativeness.Parameter ψEo, was shown to be in most defined by the F treatment, probably due to higher lightintensity compared to C. Variables regarding electron transport and dissipation showed specific reactions to Hand SH treatments. Co and LL conditions caused specific changes in in parameters VJ and VI. Further research onusability of ChlF in maize breeding is needed, as it represents the data-rich, easy to measure method, providingthe biological framework for explanation of reactions to different stresses