Peruvian Journal of Agronomy

Journal Information
EISSN : 2616-4477
Published by: Universidad Nacional Agraria la Molina (10.21704)
Total articles ≅ 57
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Suzan Abd El- Latif Kamel Ibrahim, Mohamed Ali Abdelsatar, Mohamed Abd El-Raheem Ahmed, Magdy M. Niazy
Peruvian Journal of Agronomy, Volume 5, pp 1-17; https://doi.org/10.21704/pja.v5i1.1656

Abstract:
Six divergent genotypes of sesame (Sesamum indicum L.) were crossed using a half diallel excluding reciprocal crosses, to estimate heterosis, combining ability and nature of gene action for studied traits under two irrigation regimes. The two irrigation regimes were normal irrigation conditions with amount of applied water 5952.38 m3/ha and water stress conditions with amount of applied water 2976.19 m3/ha at Etay-El-Baroud Agricultural Research Station, Behaira governorate, Agricultural Research Center, Egypt during 2019 summer season. A randomized complete block design with three replications was used for each irrigation regimes. The variation of genotypes and their components from parents, crosses and parents versus crosses were highly significant for all studied traits under both irrigation regimes and their interactions with irrigation. Variation attributable to general and specific combining ability was highly significant for seed yield and yield components under both irrigation regimes. The parents L92 and L110 were the best combiners for seed weight per plant and most of its components under both irrigation regimes. The best F1 cross combination was L92 × L110 in specific combining ability and heterotic effects over mid- and better-parents under both irrigation regimes for seed weight per plant and most of its attributes. The preponderance of additive gene action in the inheritance of most studied traits was observed, that further confirmed by its significance and the value of average degree of dominance exceeding the unity. Narrow-sense heritability varied from 0.19 for number of branches per plant to 0.47 for 1000 seed weight under normal irrigation, whereas, under water stress conditions, it ranged from 0.14 for number of branches per plant to 0.42 for fruiting zone length. Parents L95 and L93 under normal irrigation and L93 and L110 under water stress conditions carried mostly genes with dominant effects for seed weight per plant, in contrary, L92 and L110 under normal irrigation and L92 and L12 under water stress conditions carried mostly recessive alleles for seed weight per plant. Hence, the results will be used to develop a sesame breeding scheme at Etay-El-Baroud Agricultural Research Station.
Denis Paolo Cáceres Candia, Alejandro Risco Mendoza, Patricia Elena Quiroz-Delgado, Walter Eduardo Apaza-Tapia
Peruvian Journal of Agronomy, Volume 5, pp 18-24; https://doi.org/10.21704/pja.v5i1.1670

Abstract:
The flowers blight caused by Botrytis cinerea Pers. is among the most important citrus diseases, especially in cultivars whose flowering coincides with the humid seasons of the year. As a result of the pathogenic features of this fungus and the complex nature of its control, it is necessary to establish a correct plan for the usage of highly efficient fungicides. The study aimed to evaluate the effect of four chemical fungicides, such as Captan (0.25%), Propineb (0.25%), Fludioxonil + Cyprodinil (0.05%), and Iprodione (0.15%); as well as the effect of a biological fungicide, such as Melaleuca alternifolia extract (0.1%), on Botrytis cinerea Pers. Two phases were established: the first, under laboratory conditions of Department of Plant Pathology of National Agrarian University-La Molina (UNALM), evaluated the effect on mycelial inhibition at 1, 3, and 7 days after inoculation with poisoned potato dextrose agar medium. The second, under field conditions (Sayan - Huaura), evaluated the effect on incidence of the disease in flowers. In the field condition, two applications, incidence, and humid chambers were evaluated. The yield was estimated by counting the fruits. The results showed that, under laboratory conditions, Captan, Fludioxonil + Cyprodinil, and Iprodione exhibited high efficacy in the control of B. cinerea. However, under field conditions, Fludioxonil + Cyprodinil and Iprodione exhibited a significant control of B. cinerea. A similar trend was obtained for the yield estimates.
Denis Paolo Cáceres Candia, Alejandro Risco Mendoza, Patricia Elena Quiroz-Delgado, Walter Eduardo Apaza-Tapia
Peruvian Journal of Agronomy, Volume 5; https://doi.org/10.21704/pja.v5i1.1360

Sandro Sardón Nina, Raúl D. Zapata Hernández, Luis A. Arias López
Peruvian Journal of Agronomy, Volume 5, pp 25-34; https://doi.org/10.21704/pja.v5i1.1676

Abstract:
This study compared the organic carbon (OC) content in fractions of humic acids (HA) and fulvic acids (FA) in five soil orders (Aridisol, Entisol, Histosol, Inceptisol and Mollisol) and know their association with the degree of humification. Extraction and fractionation, as well as the degree of humification was carried out by the Nagoya method proposed by Kumada. OC quantification was determined by the Walkley and Black method. The results are: the average OC content of HAs of the order Aridisol differs from that of Histosols, Inceptisols, and Mollisols. The order Entisol presented differences with the Histosols and Mollisols, the soils of the order Inceptisol presented differences with the Aridisols and Histosols and those of the order Histosol differed from the Aridisols, Entisols and Inceptisols. Similarly, those of the Mollisol order differed with the Aridisols, Entisols and Inceptisols. In the fraction of FA the average OC content of the order Aridisol deferred from that found in Histosols, Inceptisols and Mollisols. The Entisol order differed from the Mollisols; likewise, the Inceptisol order differed from the Aridisols and Mollisols and the Histosol order differed from the Aridisols. Finally, the order Mollisol was also different from the Aridisols, Entisols, and Inceptisols. Soil types do not show wetting patterns, because they are not based on pedogenetic processes and these have a wide range of characteristics in surface horizons.
Sandro Sardón Nina, Raúl D. Zapata Hernández, Luis A. Arias López
Peruvian Journal of Agronomy, Volume 5, pp 35-43; https://doi.org/10.21704/pja.v5i1.1680

Abstract:
Humic substances (HS) are the main component of soil organic matter (SOM), a product of the pedogenetic process. In this study, the morphometric factors and climatic variable that condition the degree of humification, the organic carbon content of humic acids (HA) fulvic acids (FA) of 42 soil samples are related through the functional equation of factors of state of the soil proposed by Jenny. The degree of humification was determined by the Nagoya method proposed by Kumada. The quantification of organic carbon was determined using the method by Walkley and Black. The morphometric parameters of the relief were obtained from the Digital Elevation Model (DEM) and the climate parameter of the MODIS sensor. The results show that the relief factor conditions the degree of humification and the climate factor conditions the organic carbon content of humic acids (HA) and fulvic acids (FA).
Jorge Ramón Castillo Valiente, Susana Patricia Rodríguez Quispe, Walter Eduardo Apaza Tapia, Alberto Marcial Julca-Otiniano, Manuel Antonio Canto Saenz, Teresa Rosales Sanchez
Peruvian Journal of Agronomy, Volume 4, pp 75-81; https://doi.org/10.21704/pja.v4i3.1645

Abstract:
The present study was conducted in the fields of the Chavimochic irrigation, located in La Libertad Region-Peru. Prodiplosis longifila Gagné (Diptera Cecidomyiidae) is considered the key pest of asparagus and other vegetables cultivation. This study aimed to characterize the presence of this insect pest in asparagus crop under drip irrigation conditions, in order to find the best alternatives for its control. The cultivar most planted in the Chavimochic Irrigation is cultivar UC 157 and that the meteorological conditions of the area are optimal for the production of asparagus; but also for the establishment and reproduction of the insect. The morphology of asparagus is favorable for reproduction of the insect, from larva to adult, since it frequently bracts and flowers at larval stage and establishs itself at the adult stage; at the base of the plant. All experiments conducted, had at least three repetitions and the results are given on average. The insect can have many hosts and an average biological cycle of 11 days, with the highest populations in the months of May and November. Throughout the day; the adult populations are very active from 10 pm to 4 am. The drip irrigation system provides better conditions for the establishment of the insect and its reproduction in the fields, as well as the design of double row sowing so water management becomes an important factor for managing its populations. From the 100% puparium that fell to the ground, only 37.95% emerged as adults. The percentage of damaged stems per linear meter can be 70.46 and healthy stems 29.54. The number of larvae per shoot can be from 68 to 489 while number of larvae per male flower can be from 2 to 7 individuals. There is a relationship between flowering and the number or pre-pupae fallen to the ground, but as the crop develops, the adult´s number decrease, but nevertheless is still aggressive and permanent.
Peruvian Journal of Agronomy, Volume 4, pp 82-87; https://doi.org/10.21704/pja.v4i3.1649

Abstract:
Climate change is an obvious threat to agriculture, food security and conservation of plant genetic resources. Potato is a globally important food. In Peru, there is high variability and diversity of wild and cultivated species, such that they are considered as one of the region’s most vulnerable to the impact of climate change. With these considerations, we report the results of an investigation in which a preliminary screening of the reaction to drought of 67 native potato morphotypes was conducted to verify for differences in morphological indicators of growth, development, and production of tubers in response to continuous irrigation (CI) and restricted irrigation (RI) treatments. In the course of this study, 21 irrigations were applied to plants by CI (every 1-2 days) and, in the same period, 7 irrigations were applied to plants by RI (every 5-6 days). Comparison of characteristics average in all the morphotypes with plants under CI and RI, indicated that RI did not show differences in height of plants, length of internodes, or leaf and terminal leaflet indexes, and that RI reduced the stem thickness and dry weight of foliage. In this study, we highlight the morphotypes whose plant characteristics present higher averages with respect to their clonal counterparts that were treated with CI. The positive relationship between the number and weight of tubers harvested, as well as the significant reduction of both components of low RI yield is confirmed. In addition, we also highlight the response of some morphotypes that present higher tuber yield under RI. The native morphotypes that were identified as tolerant (according their responses in the characteristics of their plants and yield of tubers under RI) are as follows: BGR 19 (“Rayhuana”); BGR 99 (“Yuracc ñahui hualash”); BGR 170 (“Yana utcush”); and BGR 238 (“Muru huayro”).
Kripa Adhikari, Sudip Bhandari, Laxmi Dhakal, Jiban Shrestha
Peruvian Journal of Agronomy, Volume 4, pp 121-133; https://doi.org/10.21704/pja.v4i3.1495

Abstract:
Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), Fall Armyworm (FAW) is a crop pest with more than 80 host species causing severe damage to maize cereals. FAW, native to the tropical and subtropical region of America, has rapidly spread worldwide. The larvae and adults of FAW damage young leaves, leaf whorls, tassels or cobs of maize. Under heavy infestation of FAW cause 50-80% yield loss in maize crop. This pest is capable of rapidly breeding, migrating and feeding on a large variety of host plants, making it very difficult to monitor. However, there are several control measures reported in various countries. Integrated pest management (cultural, chemical, and biological) is widely used to control this pest. Because the pest has become resistant to many insecticides, its use is not recommended at the initial stages of infestation. But, the last choice for this seriously infested pest management is the use of pesticides below the economic threshold level. This review focuses on insect distribution, biology, maize damage, and possible strategies for its management.
Ernesto Díaz-López
Peruvian Journal of Agronomy, Volume 4, pp 88-92; https://doi.org/10.21704/pja.v4i3.1650

Abstract:
In order to know the effect of three levels of potassium on five eco-physiological parameters in sunflower, open-pollinated achenes Victory cultivar, were sown at a density of 11.08 plants m-2 with a fertilization of 100N-50P kg ha-1 N=nitrogen, P= phosphorous, K= potassium. Traits evaluated were: agronomic yield, leaf area index, light attenuation coefficient and intercepted radiation. The treatments consisted of three potassium levels: 0, 50 and 100 kg ha-1 (K2O) and four repetitions (3x4) resulting in 12 experimental units, which were evaluated under a randomized complete block design. The results indicate that the application of 50 and 100 kg ha-1 of potassium increase the agronomic yield, leaf area index, intercepted radiation as well as the light attenuation coefficient. From this investigation it can be concluded, that potassium is a very important nutrient for sunflower when it is sown in dry climates such as the Tehuacan valley, Puebla.
Juan Nolasco-Chumpitaz, Paul Ccoyllo-Llacsa, Gabriela Koc-Sanchez, Percy Medina-Morales
Peruvian Journal of Agronomy, Volume 4, pp 93-103; https://doi.org/10.21704/pja.v4i3.1341

Abstract:
The aim of this study was to characterize and identify groups of achiote (Bixa orellana L.) with characteristics related to increased yield and bixin content. A total of 149 achiote accessions were collected from the departments of Loreto, San Martin, Junín, Pasco, Huánuco, Ucayali, and Cusco, in Perú. These were then evaluated using ten quantitative and three qualitative capsule and seed descriptors. Undesirable characteristics such as high spinosity and dehiscence predominated, while none of the quantitative descriptors correlated significantly with bixin content. Principal component analysis indicates that the quantitative descriptors (except for bixin content) are statistically significant, forming four clusters. Notably, one of the clusters included accessions characterized by heavy seeds, and another cluster included accessions with high number of seeds and bixin content.
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