Category Archives: Volume 10 No. 2 (1988)

Note: Effect of Sett Size on the Growth, Development and Yield of Taro


Author(s): Selvano S. Dalion, Jose R. Pardales, Jr. and Mario E. Baliad

Abstract

Size of planting material greatly affected the growth and development of taro. Most of the vegetative characters and man corm yield increased in values as sett size increased. A very strong positive correlation was observed between sett size, and fresh and dry weights of main corms. Regardless of the sett size, growth curves of the different plant components showed similar patterns following the same time course. Progressive reduction in leaf are ensued 5 months after planting thus, corm yield of small setts cannot be the same as yield of large setts even if growing period is prolonged.

Keywords : Taro. Sett size. Corm yield. Growth curves.

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Note: A Comparison of the Pressure Chamber Apparatus and Shardakov Method in Determining Leaf Water Potential of Cassava and Soybean


Author: Valerio C. Tanguilig

Abstract

The efficiency of the Shardakov or dye mothod in measuring the leaf water potentials of cassava (Manihot esculent Crantz var. Hawaiian 4) and soybean (Glycine max [L.] Merr. var. Clark 63) was evaluated and compared with that of the pressure chamber measurements were made on whole leaves while Shardakov method measurements were made on leaf discs. A regression analysis showed an agreement between the two methods. Results indicate the Shardakov or dye method is as useful as the pressure chamber apparatus in measuring the left water potentials of cassava and soybean.

Keywords : Cassava. Leaf water potential. Pressure chamber apparatus. Shardakov method. Soybean. Sucrose solution. Water stress.

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Social and Economic Factor Associated with Farm Level Technology in Carabao Raising


Author(s): Alicia S. Agarcio, Nerelito P. Pascual, Edgardo A. Pañares and Leonora M. Densing

Abstract

The study dealt with the general characteristics of the respondents, existing management practices employed, some socio-economic factors associated with carabao raising, and the gap between the recommended and existing management practices in carabao raising in Iloilo, Bohol and Leyte.
Generally, the respondents were farers in their late forties, predominantly male, mostly married and fifth graders who were engaged in carabao raising for more than 201 years. Rice-, corn-, coconut-, sugarcane-, rootcrop- and vegetable-based farming systems were practiced in the three locations with rice-based farming as the most widely used.
Most of the carabaos raised were intended primarily for draft purposes. The native strain was the most predominant among the breeds raised. Several management practices such as tethering, wallowing, feeding soilage, confining, castration, breeding and training for draft were employed.
Adoption of recommended practices was associated with tribe, number of persons involved, beliefs, years in carabao raising, peace and order condition, number of animals raised, gross income, distance to market, types of road, and number of animal days.

Keywords : Carabao raising. Socio-economic factors. Technology level.

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Designing a Participatory Media-Assisted Learning System for Small Lowland Rice Farmers


Author: Monina M. Escalada

Abstract

With the results of the baseline study as the basis for designing a learning system, a user-oriented media-assisted learning system was evolved. It consisted of a staggered farmers’ class with a lecture by an agronomist, dramatized audio tapes and discussion, informal talks between the agronomist and farmers, and periodic farm visits.
Although participatory mechanisms in the planning, development of materials, utilization, and evaluation of the learning system were explored, such approach was only possible at the planning and utilization stages because of the farmers’ low functional literacy level.
Based on participant observation, the dramatized audio tapes motivated people to gather for a farmers’ class; sustained the attendance; combined entertainment and learning; and reached remote areas which are not reached by Ministry of Agriculture and Food extension personnel.

Keywords : Media-assisted learning system. Participatory approach. Information needs. Rainfed lowland rice production.

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Effect of Azolla as Source of Nitrogen on the Growth and Yield of Pechay (Brassica napus L. var. chinensis)


Author(s): Zenaida M. Cuevas, Rebecco M. Santiago and Elizabeth D. Briones

Abstract

Plants applied with either azolla or inorganic fertilizer performed better than the unfertilized ones. Increasing the rate of azolla application from 120 to 210 kg N/ha correspondingly increased all the parameters measured and the net income during the first cropping. However in the second cropping, all the parameters considered and the net income tremendously decreased. Highest yield and net return in both croppings were obtained from application of 210 kg N/ha from azollla while the unfertilized control showed the lowest values.
Application of the same amounts of nitrogen (165 kg N/ha) from azolla (T3) and inorganic fertilizer (T1) did not produce significant differences in all parameters during the first cropping. However during the second cropping, T3 but not T1 produced higher average weight per plant and yield than the control.
The soil pH and organic matter, phosphorus and potassium contents increased as the rate of azolla application was raised from 120 kg to 210 kg N/ha.

Keywords : Azolla. Pechay. Nitrogen. Organic fertilizer.

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Genetic Variation in a Wide Gene Base Population of Sweet Potato [Ipomoea batatas (L) Lam ]


Author(s): Algerico M. Mariscal and Azucena L. Carpena

Abstract

Design I mating system was used to estimate the components of genetic variation of sweet potato base population. Characters studied were total root yield, weight and number of marketable roots, total number of roots, fresh weight of wines, harvest index, scab rating and dry matter content of roots. Significant additive and dominance genotypic variances ware observed in the population with high magnitude of the latter in all characters except in scab rating and dry matter content obtained suggest that the population may be improved using any available intrapopulation selection procedure like mass selection and full-sib family selection for the characters mentioned. Selected individuals or full-sib families can be intercrossed to utilize the high dominance variation in the population. Dry matter content of the roots with its very low coefficient of variability, is considered the most reliable basis for selection in this population.

Keywords : Sweet potato. Ipomoea batatas. Genetic variation. Wide gene base population. Mass selection. Full-sib family selection. Design I mating system. Root yield.

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Phenolics Involvement in Sweet Potato Resistance to Meloidogyne incognita and M. javanica


Author(s): Ruben M. Gapasin, Rodrigo B. Valdez and Evelyn Mae T. Mendoza

Abstract

The possible involvement of phenols in sweet potato resistance to root-knot nematode was shown by the reduced number of eggs hatched and high larval mortality of Meloidogyne incognita and M. javanica exposed to root extracts of the resistant cultivars even as low as 10% concentration. The compounds present in the extracts were heat resistant, of low molecular weight and water soluble.
Thin layer chromatography (TLC) revealed two distinct groups of blue fluorescent spots in susceptible and resistant sweet potato extracts with Rf values corresponding to chlorogenic acid, scopoletin and esculin. More phenolics accumulated in root extracts of resistant sweet potato cultivars following infection as indicated by the stronger color intensity of the fluorescent spots.

Keywords : Sweet potato. Meloidogyne incognita. M. javanica. Thin layer chromatography (TLC). Chlorogenic acid. Scopoletin. Esculin. Phenolics.

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Host Influences on Epidemic Development of Peanut Leaf Spot Caused by Cercosporidium personatum (Berk. And Curt) Deighton


Author: Rodolfo A. Paningbatan

Abstract

Based on one cycle of pathogenesis due to peanut leaf spot fungus, Cercosporidium personatum (Berk. and Curt) Deighton, resistant cultivars PI 259747 and EC 76446 (292) significantly prolonged the latent period of the disease by almost two times that of susceptible cultivar CES 101. This indicates 50% reduction in the potential number of nonoverlapping disease cycles that could be generated during the course of the epidemic. PI 259747 sustained a four-fold slower rate of lesion enlargement and six-fold less spore production rate than that of CES 101 based on data taken at 4,5 and 6 weeks after inoculation. Sporulation rate was positively related to the rate of lesion enlargement (r= 0.86). Possessing some of the rate-reducing resistance traits, cultivars PI 259747, NC Acc 17133 (RF), PI 350680 and EC 76446 (292) significantly slowed down the progress of leaf spot epidemic in the field by 55-75% relative to that of CES 101. PI 259747 and NC Acc 17133 (RF) distinctively reduced the numerical increase of lesions by 85% relative to CES 101 within 6 weeks from disease onset.

Keywords : Peanute leaf spot. Cercosporidium personatum. Rate-reducing resistance. Infection rate.

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