Recipients of the different sweet potato varieties and accessions from MMSU are now enjoying the robust growth of their crop.

Mr. Lyndon Madrid, one of the recipients from Brgy. Bungcag, Dingras, shared the green and purple vibrance of his farm with the seven sweet potato varieties and 15 accessions he obtained from MMSU. According to him, these will serve as source planting materials during the planting season for sweet potato this year as he identifies potential value-adding and market in their locality.  

These varieties and accessions, along with relevant information and technologies on sweet potato production, were shared to the public this February through Mr. Pio Belen of the Research Directorate in an interview conducted by Ms. Mercy Gano of the Extension Directorate and Mr. Constante Julian of the Research Directorate.  Other recipients of these varieties and accessions include Mr. Hisham Dabucon of Banna, and Mr. Joel Cadalzo of Capurectan, Solsona, Ilocos Norte.

According to Mr. Belen, ‘sweet potato is a well-known crop in the country. It is a good alternative food when there is scarcity of rice especially in this time of pandemic’. As a good alternative, he shared that research showed that sweet potato contain 769% Vitamin A, 65% Vitamin C, 29% Vitamin B6, 15% Magnesium, 27% potassium, 16% copper, 50% manganese, 50% phosphorous, 28% dietary fibres, and 8% protein which makes it’s a good food for the health.

Mr. Pio Belen is the project in-charge of the Sweet Potato and Cassava Project of the MMSU. According to him, the following pointers and tips need to be considered.

Planting time 

In the Ilocos, this crop is best planted from the second week of October, the whole month of November and December when the climate is generally favorable for the year. For these recommended months of the year, it is best to plant during these months for tubers purposes.

The last quarter of the year is best recommended because radiation from the sun enhances the growth of tubers. When the crop is planted in November, rooting of tubers are induced because they are fully exposed in the sun. When planted during rainy season, rooting is prohibited which lowers yield.  

Ideal soil type 

Sweet potato is best planted in a sandy-loam type of soil. This soil type allows a more breathable space for the roots of the crop. Lesser incidence of attacks of weevil can also be observed when planted in this kind of soil. The sand hinders the weevil from reaching the tubers, hence, lesser damage of the tubers.  

In contrast, if the crop is planted in clay-loam type of soil, there is a greater chance for weevil to damage the tubers because cracking of the top soil serve as ways for weevil to come in contact to the tubers.

Planting and Cultural Management

From Mr. Belen, in planting sweet potato, planting material should be cut at 30 cm each and planted at a distance of 1 meter between rows.

For its fertilizer requirements, it is recommended that before planting, complete fertilizer is immediately applied at basal application to boost its growth. In its vegetative stage or upon reaching 21-30 days, urea will be applied. 

The crop needs 4-5 times irrigation depending on the soil type where they are planted. For sandy-loam, the crop needs to be irrigated 4-5 time; for clay soil, four times irrigation is recommended.

In irrigating sweet potatoes, the first irrigation is at planting. At vegetative stage when the stems already start crawling at least one meter, another irrigation is needed to boost their growth. At root formation or at 30-40 days, another irrigation by way of flooding. At 20-25 days after the third irrigation, another flooding irrigation is recommended.

It is also important to note that hilling up at 30 days when the stem is already a meter long. This is to let the soil more friable and to let the air come in contact with the root system.

Harvesting

Sweet potato can be harvested at 90-100 days during the dry season after planting for marketing purposes. The tubers is ideally harvested at 100 days.  If the sweet potato is harvested at 100 days onwards, there is a bigger chance for weevil to attack the tubers.

It is important to note that if the crop is planted for tubers purposes, harvesting the tops is not advisable. According to Mr. Belen, harvesting the tops reroutes the nutrients to go out. Hence, for better and bigger tubers, topping should not be done.

Sweet Potato varieties and accessions

Mr. Belen recommends six sweet potato varieties: Kiringkit, VSP 16, PSB SP 17, PSB SP 19, UPL SP 11, and NSIC SP 25. The first four sweet potato varieties, VSP 16, PSB SP 17, PSB SP 19, and UPL SP 11 are best recommended for dry season planting because of its high yielding ability. NSIC SP 25 yields lower than the rest, however, highly acceptable and has sweeter taste when boiled.  

Distinguished by the characteristics, VSP 16 has a violet skin with yellow flesh; PSB SP 17 has a heart-shaped leaves with a violet skin and yellow flesh; UPL SP 11 has violet flesh with yellow skin; and NSIC SP 25 white skin, violet flesh, and a water spinach-like leaves.

For the MMSU accessions, Accessions 1 and 3 are sweet, and 4 has sweet taste with white skin and flesh. Accessions 6, 9, and 10 are also good for dry season planting and has more yield. All these accessions have heart-shaped leaves.

The MMSU Collection, from its 23 sweet potato collection, has seven high-yielding varieties sweet potato varieties recommended for tubers to include PSB 17, VSP 16, PSB 19, VSP 2, and NSIC SP 25. According to Mr. Belen, VSP 16 yields 27-28 tons per hectare; PSB varieties yield a range of 25-28 tons per hectare; the sweet and delectable NSIC SP 25 with 22 tons per hectare; and the PSB SP 1 with 24 tons per hectare. It is important to note that Accession 8 with an orange flesh and violet stem bears fruit even during rainy season.

For tops, the kiringkit that is commonly sold in the market, is best recommended for tops for its water spinach-like leaves and good eating quality. All the accessions are acceptable for their tops but kiringkit is highly acceptable.  Accession 6 is bush-type with good eating quality.

For processing purposes, PSB 17, PSB 19, NSCI 31, PSB 16 are recommended.

Other information

            On the note of using chemical fertilizers, Mr. Belen recommended that spraying insecticides be done only when insects are seen in the crops. In using insecticides, use only the recommended dosage at the specified time and number of day. Spraying may not be eliminated in practice especially when other crops are planted near them. In embracing organic farming, isolating the crops from crops with common insects is recommended.

            Other problems in growing sweet potato include weeding to eliminate or reduce weeds, insect infestation, hilling up the crop, and stray animals. For these, diligence and frequent monitoring of the crops is recommended to devise solutions.

Sharing to the Community 

The interview was aired to partner radio stations, DWFB Radyo Pilipinas-Laoag and DWNI Radyo Karruba-Burgos, through Ms. Mercy Gano of the Extension Directorate and Mr. Constante Julian of the Research Directorate.

            Through this knowledge-sharing, more sweet potato growers are equipped with new knowledge in managing their crops. Furthermore, this distribution to community members envisions more farmers and growers adopting these planting materials, hence, the bigger possibility of expanding its production in the regions and soliciting valuable feedbacks in their growth and abundance in different localities. In the bigger picture, these sweet potato varieties and accessions from the MMSU are hoped to help sustain a food secure, healthy, and hunger-free Ilocos Norte, especially in this time of pandemic. With tops and tubers, there shall be food in the dining table and more income for the family.

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