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March 2020, Vol. 103 No. 1

Abaca ‘Abuab’ variety with high fiber quality trait but susceptible to bunchy top disease characterized by narrow and stiff leaves, and severe bunchy top symptoms of stunting and crowding of leaves at the apex.

{Photographs courtesy of Filomena C. Sta. Cruz, Ph.D., Institute of Weed Science, Entomology and Plant Pathology (IWEP), College of Agriculture and Food Science, University of the Philippines Los Baños, 4031 College Laguna, Philippines}



Characteristics of Selected Hybrids of Abaca (Musa textilis Nee) with Resistance to Bunchy Top
Elizabeth P. Parac, Antonio G. Lalusin, Ireneo B. Pangga and Filomena C. Sta. Cruz

Received: 06 August 2018/ Revised: 15 November 2019/ Accepted: 09 January 2020

Two abaca hybrids namely, Hybrid 2 and Hybrid 7, which were derived from a cross between the resistant wild banana (Musa balbisiana) var. Pacol and the susceptible abaca var. Abuab possessing the high fiber quality trait, have been previously selected with promising resistance to bunchy top disease. In this study, the responses of these hybrids to virus inoculation by the aphid (Pentalonia nigronervosa) under screenhouse condition and to natural infection in the field were characterized. Under screenhouse condition, Hybrid 7 did not show the bunchy top disease symptoms of dark green streaks on veins and midribs, marginal leaf chlorosis, narrow and stiff leaves or upright and crowding of leaves at the apex of the plant, while Hybrid 2 expressed the disease in only 1 of 15 (7%) plants tested over the 6-mo observation period. The virus was not detectable by enzyme-linked immunosorbent assay (ELISA) using polyclonal antibody against Banana bunchy top virus (BBTV) in all asymptomatic Hybrid 2, Hybrid 7 and ‘Pacol’. Plants were confirmed negative for BBTV when tested by polymerase chain reaction (PCR) using the primer pair BBT1 and BBT2 that amplifies the 349-bp fragment of viral DNA-R component. The response was observed under condition of high disease pressure wherein the susceptible ‘Inosa’ and ‘Abuab’ developed severe disease characterized by high disease incidence, high amount of disease (measured by the Area Under Disease Progress Curve), and severe symptoms. The results observed under screenhouse condition were consistent with the response to natural infection involving plants that had been grown for 5 yr (2012–2017) in the field located at the Caraga State University, Ampayon, Butuan City, Philippines. Disease index was 4% for Hybrid 2 and 0% for Hybrid 7, indicating a resistant response to bunchy top. Knowledge on the resistance characteristics would be useful information for proper field deployment of these hybrids, and for breeding varieties with resistance to bunchy top.

Morphological Characterization and Karyotype Analysis of Abaca (Musa textilis Nee) and its Hybrids with Musa balbisiana Colla
Deziree A. Labrador, Antonio G. Lalusin, Mariecris Rizalyn R. Mendoza and Celia B. dela Viña

Received: 20 February 2018/ Revised: 23 August 2019/ Accepted: 03 February 2020

To determine if progenies from the cross between Musa textilis Nee (2n = 20) and Musa balbisiana Colla (2n = 22) produced at the Institute of Plant Breeding (IPB), University of the Philippines Los Baños are true hybrids, abaca cultivars (Abuab and Inosa), a banana cultivar (Pacol), and their back crosses (BC1, BC2, and BC3) were characterized morphologically and cytogenetically. Agronomic characters and fiber quality assessment through ANOVA and pairwise analysis revealed significant differences in tensile strength and agronomic parameters, namely, fiber quality and percent fiber recovery, except for leaf sheath number and girth measured at the top. This confirmed the recovery of recurrent parent genome (abaca) until the third generation of backcrosses. Moreover, this study reports the successful optimization of cytogenetic techniques. The most favorable time of root tips collection was from 10:00 a.m. to 10:30 a.m. due to the high number of dividing cells observed compared to other time slots tried. Two-hour cold shock pre-treatment resulted in considerably larger chromosomes, and higher number of well-spread prometaphase cells that helped in the construction of karyograms. Chromosome characteristics based on chromosome count and relative length were determined and compared among plant samples. Comparative karyotyping revealed a diploid chromosome number of 2n = 20 for abaca cultivars and hybrids. Inosa, another cultivar of M. textilis Nee, was observed to have a diploid chromosome number of either 2n = 20 or 2n = 22, in contrast to an earlier report of 2n = 17 to 2n = 23.

Hexaploid-Tetraploid Landraces and Wild Species of Wheat Revealed Diversity for Antioxidants and Total Phenolics
Huma Tariq, Shahid Iqbal Awan, Syed Mubashir Sabir and Muhammad Ilyas

Received: 15 February 2019/ Revised: 20 September 2019 and 19 January 2020/ Accepted 12 February 2020

Wheat contains various phytochemicals, most importantly, antioxidants and polyphenolic compounds that have a variety of health-promoting effects. Seed material was obtained from 63 wheat genotypes of three species (T. aestivum, T. durum, and T. sphaerococcum) from Pakistan and Syria. This study was initiated to estimate and compare the interspecific and intraspecific diversity for antioxidant activity (AOA) and total phenolic content (TPC) in different species of wheat. The wild relatives and landraces of three wheat species exhibited a highly significant interspecific and intraspecific diversity for both traits. T. aestivum exhibited more intraspecific diversity. The AOA of the genotypes ranged from 7.45% to 41.68%, being maximum in accessions of T. durum 12977 (41.68%). TPC ranged from 10.09 to 39.28 mg GAE g-1 and was highest in T. durum accession 12999 (39.28 mg GAE g-1). The lowest AOA (7.45%) and TPC (10.09 mg GAE g-1) were observed in T. aestivum landrace LR-27. Hence, T. durum accessions 12999 and 12979 could be our desired accessions for future breeding programs having phytochemicals. Cluster analysis distributed the genotypes into four clusters. Genotypes of different origins grouped differently, indicating an environmental influence in the development of their genetic architecture. Cluster analysis indicated that 41.30% of the genotypes were included in the high AOA and TPC group. Members of T. aestivum that grouped in clusters 1 and 2 showed low to moderate AOA and TPC. The accessions of T. durum and T. sphaerococcum performed much better than T. aestivum for both of the biochemical traits.

Effect of Tillage Systems on Soil Properties and Yield of Wheat and Rice in Rotation
Shumin Liang, Ruizhi Xie, Zhu Zheng, Muhammad Abdul Rehman Rashid, Yonglu Tang, Yuee Liu, Jinzhong Yang, Chaosu Li, Bing Chen and Shaokun Li

Received: 26 October 2018/ Revised: 23 October 2019/ Accepted 06 January 2020

Effect of four tillage systems (1) winter wheat and rice rotary tillage (WRRT) (CK), (2) winter wheat and rice no-tillage system (WRNT), (3) winter wheat no-tillage and rice rotary tillage (WNRR), and lastly, (4) winter wheat and rice no-tillage in a raised bed (WRNB) on soil properties and crop yields was investigated in a field experiment in 2004–2010 in a wheat-rice crop rotation on the Chengdu Plain, China. The WRNT system significantly increased the saturated hydraulic conductivity and water infiltration relative to the WNRR and the WRRT (CK) systems. The soil cone penetration resistance was greater in certain soil layers beneath the three systems, compared to the CK system (P < 0.05). The three tillage systems also significantly increased soil erodibility K (P < 0.05) and soil organic matter (SOM) (P < 0.05) in certain soil layers but had no significant differences in the soil bulk density, total porosity, and specific gravity among the four tillage systems. Additionally, WNRR improved the wheat yield by 4.0% and rice yield by 8.8% relative to CK.

Effect of Zinc Chelate and Sulfate on Mineral Content, Antioxidant Activity and Grain Yield of Vigna unguiculata L.
Veronica Estrada-Dominguez, Esteban Sanchez-Chavez, Efrain de la Cruz Lazaro, Cesar Marquez-Quiroz and Rodolfo Osorio-Osorio

Received: 27 June 2019/ Revised: 24 January 2020/ Accepted: 27 January 2020

The study evaluated the effect of applying different doses of zinc sulfate and zinc chelate on the mineral content, antioxidant activity, and yield of grains of cowpea bean (Vigna unguiculata L.). Doses of 7, 14, and 28 mM L-1 of zinc sulfate and chelate were assessed against a distilled water control. In the plants, the days to flowering as well as grain weight, number of pods, and number of grains per plant were recorded. Meanwhile, in the grains, antioxidant activity, phenols, phytic acid, and mineral content were determined. Results indicated that biofortification with 7 and 14 mM L-1 of sulfate and zinc chelate increases earliness in flowering, the number of grains per plant, and the grain yield in addition to improving the mineral content of the grains. The highest antioxidant activity was found with the zinc chelate treatments. Phenol content increased with the zinc chelate and sulfate doses, while the phytic acid content decreased with respect to the control. Biofortification of cowpea beans with zinc chelate and sulfate at 28 mM L-1 induced the highest accumulation of Zn in cowpea seeds. It is thus feasible to implement a biofortification program with zinc in cowpea beans to increase the zinc content, the mineral content, antioxidant activity, and phenol content in the grains, as well as to decrease the phytic acid content.

Synthesis and Characterization of Nano Zinc Oxide Foliar Fertilizer and Its Influence on Yield and Postharvest Quality of Tomato
Quincy E. Ybañez, Pearl B. Sanchez, Rodrigo B. Badayos and Josephine U. Agravante

Received: 24 September 2018/ Revised: 13 November 2019/ Accepted: 06 January 2020

Nanoparticles of ZnO were synthesized via an alkaline precipitation technique that is ideal for large-scale and cost-effective production, using ZnSO4 and ZnCl2 as starting materials. Scanning electron microscopy (SEM) analysis revealed that rod-shaped ZnO crystals with nanoscale dimensions were produced from both precursors, but ZnCl2 produced smaller and less aggregated crystals compared to ZnSO4. Using ZnCl2 as starting material, we refined the synthesis parameters by varying the solution pH and temperature, drying and calcination temperature, and adding cationic surfactant. Scanning electron microscopy – energy dispersive x-ray spectroscopy (SEM-EDS) analysis verified the nano size of ZnO (average of 45 nm via SEM), with low degree of aggregation, and high chemical purity (59.96% Zn via EDS). X-ray diffraction (XRD) patterns identified hexagonal wurtzite structure with high crystallinity. Mineralogical analysis by X-ray fluorescence (XRF) showed that the nano ZnO were free from impurities (90.39% ZnO) while FTIR analysis authenticated the presence of Zn and O bonds. There was sufficient evidence to conclude that nano ZnO with high chemical purity, and suitable characteristics as Zn foliar fertilizer source, was successfully synthesized using ZnCl2 as starting material. The synthesized nano ZnO (SNZ) was tested as foliar fertilizer on pot-grown ‘Marimar’ F1 tomato, and compared with bulk ZnO (BZ), commercial nano ZnO (CNZ), and granular zinc sulfate (ZS). Boric acid was incorporated to a separate set of the Zn foliar treatments (SNZ+B, BZ+B, CNZ+B, ZS+B) to determine the synergistic effects of Zn and B on the growth and yield of tomato. SNZ+B resulted in positive responses in Zn and B uptake and dry matter yield. Marketable yield was found to be significantly highest in SNZ+B. Statistically, SNZ+B was either better than or equal to the SNZ and CNZ+B treatments in terms of the growth and yield parameters. SNZ+B also led to significant improvements in fruit quality, including higher TSS, %TA, and ascorbic acid content. SNZ enhanced the agronomic effectiveness of Zn foliar fertilizers as evident in the improvements in yield components of tomato. Nano-scaling made ZnO more available to stomates, making nutrient use more efficient. It also resulted in increased number of particles per unit weight of applied Zn, while increasing the specific surface area and solubility of ZnO in water, thus enhancing plant uptake which ultimately led to improvements on yield as well as postharvest quality.

Fruit Thinning Enhances Yield and Quality of Local Apple Fruit (Malus domestica Borkhausen) Var. Gaja in Pakistan
Noor Rehman, Asif Latif, Malik Muhammad Hashim, Atiq Ahmad Khan, Syeda Mehwish Gillani, Hakeem Ullah Khan and Muzafar Ali

Received: 30 April 2019/ Revised: 21 September 2019/ Accepted: 06 January 2020

The apple tree usually has heavy fruit set but to improve the individual fruit size, apple growers reduce the number of fruits by thinning. The present study was carried out to assess yield and quality of apple fruit as influenced by fruit thinning. The experiment was carried out in a randomized complete block design (RCBD), with two factors, viz. time of thinning (factor 1) and amount of thinning (factor 2). Factor 1 included thinning after 2 wk of fruit set and 4 wk after fruit set; Factor 2 included one fruit per cluster, two fruits per cluster, three fruits per cluster, and four fruits per cluster. Each treatment was replicated three times. The indigenous apple germplasm Gaja was selected for the experiment. Fruit diameter, fruit length, fruit weight, fruit color, total soluble solids (TSS), and fruit pH were significantly improved by fruit thinning intensity while total yield, fruit drop percent, number of fruits per kg and fruit firmness were reduced by increasing thinning intensity. Leaving 2–3 fruits per cluster not only improved the fruit size (diameter and length) but also gave maximum economic return.

Feasibility and Financial Viability of an Intensive Mustard–Mungbean–Transplanted Aus Rice–Transplanted Aman Rice Cropping System in a Non-Saline Coastal Ecosystem of Bangladesh
M. S. Islam, Akbar Hossain, Jagadish Timsina, H. Saif, M. M. R. Sarker, A. S. M. M. R. Khan, M. K. Hasan, T. Zahan, Ayman EL Sabagh, Hakki Akdeniz and Celaleddin Barutçular

Received: 28 February 2019/ Revised: 29 September 2019/ Accepted: 06 January 2020

Even as Bangladesh has achieved remarkable progress in food production, especially rice production, there is growing concern about how to feed its increasing population in the future since natural resources such as agricultural land and water are shrinking and undergoing degradation due to climate change. With the country’s limited agricultural land area, horizontal expansion for crop production is hardly possible; on the contrary, vertical expansion is possible through increase in crop yield per unit area and reduction of production losses. Such expansion is only possible in the non-saline coastal areas where overall cropping intensity is lower compared with other parts of the country. To test this hypothesis, an experiment was conducted in a non-saline coastal ecosystem of Bangladesh in 2015–2016 and 2016–2017 to evaluate the feasibility and financial viability of a four-crop-based cropping pattern, i.e., Mustard–Mungbean–T. Aus–T. Aman against the farmers’ three-crop-based pattern ‘Mustard–Dibbling Aus–T. Aman’. After 2 yr, it was observed that the improved cropping pattern produced 19.4 t ha–1 of rice equivalent yield compared to only 10.7 t ha–1 in the farmers’ cropping pattern. Land use efficiency and production efficiency in the improved cropping patterns were 94.3% and 36.8 kg ha–1 d–1, respectively, compared to only 79.7% and 28.3 kg ha-1 d-1 in the farmers’ cropping pattern. Gross margin in the improved cropping pattern was 1914 US$ ha–1 whereas it was 924 US$ ha–1 in the farmers’ cropping pattern. The marginal benefit cost ratio of the four-crop-based cropping pattern was 2.38 over the farmers’ cropping pattern. In both patterns, there was negative apparent nutrient balance for K but positive balances for N and P. Based on productivity and economic returns, the study suggests that the improved four-crop-based cropping pattern is feasible and financially viable in the non-saline coastal zone of Bangladesh. These results will also have implications for the adjacent coastal ecosystems in India.


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