How do yams reproduce

However, I will be moving several hours South by car and will either have to transplant my plant in the car and replant it in our new home, or harvest them soon. Which is my best bet?

Just checking. Can you take the plant with you, with the box and vines intact? If not, you can dig around in the box and see how big the roots are and decide then whether to take it altogether or harvest what you find.

My question is, can sweet potatoes be planted this way as well? The idea of using old tires as planters is not something we can get behind recommend , Sure, some sources suggest that they are safe short term biodegradation being a long term process and they are harmful if they have been burned or are shredded for use. It just seems that there are so many things that can be used as containers why get tires involved.

I read that vulcanised rubber contains high levels of heavy metals and other toxic compounds. I don't know whether they would definitely leach into soil and plants but I would avoid using tires for growing anything. We planted sweet potato slips and half of them were eaten, rabbits.

A few of the nibbled vines still had a slight green slip poking out of the ground. Will the slips die or continue to grow? Try to protect the remaining slip; cover them carefully with screening or something like but closer woven than chicken wire. The slips might make it. I've had this potato patch for over a year. I decided to dig it up today.

March 30, They are really small, very hard and white. What are these? I'm new at this. I halved a sweet potato and placed the exposed surface in a glass with water. They sprouted beautiful leafy green stems! The stems are bushy and maybe 6 inches long now. Did I wait too long to plant them in the soil? If I twist them off, I fear breaking the stem and roots. Can't I just carefully slice around each stem and try to not disturb the roots- planting the slip with a margin of original potato around it?

I harvested my first crop of back yard sweet potatoes today, Houston area. Late harvest, I know. They have been in since May and it is been too wet. Some of the sweets looked like they have ridges, other look bit. I saw grubs in my bed and will take steps to treat them. My question - what do I do with the damaged potatoes?

If I can remove the portion of the potato with the damage, are they safe to eat or cure for slips for next year?

If these were our sweets we would cut out the damaged area and proceed as normal—eating them or slipping them. I cut a sweet potato from last year's crop and suspended both halves in a jar of water. Each half produced a number of slips; in total. I planted the slips in our community garden and had a great harvest. The original potato halves were left outside in water throughout the summer. They made it through to the fall when one was eaten by a chipmunk. I took the second one inside, cut the bottom off of it, and placed it back in water.

It immediately began producing roots and slips are starting to sprout. Can I expect this potato to continue producing slips?

Will they be of any value if they make it to the spring? They're doing all this in November as the days grow shorter. Jim, it sounds like you have found the eternal sweet potato. If a slip is a slip is a slip, those that your tuber is producing should be fine—if they make it to spring.

That could be the challenge. We had too much hard rain in south Texas that washed the soil off the top of my sweet potatoes. They're not ready to harvest yet. Should I cover them with soil for the next month? We planted our sweet potatoes the 3rd of June, due to the rainy Iowa weather we could not harvest until Oct. The average size of each potatoe is approx.

They are way to huge, bit the flavor is good. Would they have been a lot less in size if harvested a month earlier? Thank you. I bought some sweet potato seeds from Amazon last year but when they arrived there were no instructions as to how to start seeds. Can you help me with instructions as it is time to get going this spring? Skip to main content. You are here Gardening » Growing Guides. Planting, Growing, and Harvesting Sweet Potatoes. By The Editors. When to Plant Sweet Potatoes Sweet potatoes are not grown from seed.

The trick is to plant them early enough for them to mature properly, but not early enough for them to get killed by a late spring frost. Before planting, make sure you have a long enough growing season. Most varieties will take about three to four months to mature — about 90 to days. See your frost dates and length of growing season. Can I grow sweet potatoes from a sweet potato? Slips are available at garden centers, nurseries, internet catalogs, and from local farmers when ready to plant.

Just be sure to inquire about the variety. Generally, tubers from the cut setts are milked or harvested after seven to 12 months depending on the variety and agro-ecology. Setts that sprout earlier have a longer growth period because the crop is harvested when the dry season sets in and plants senesce. In the Federal Capital Territory FCT and some yam producing States of Nigeria such as Niger, Kogi and Nassarawa, some ware sized tubers are cut into sections during the first harvest and buried again with the stump or corm left after milking in the same mound.

At the end of the season 2 to 3 months later , these setts with well-suberized surfaces but without sprouts, are dug up and planted immediately for the next crop Aighewi Sprouting starts only after the dormancy period for the variety is broken. Farmers claim that the setts with suberized surfaces rot less than freshly cut ones when planted during hot weather as is done in most parts of the yam growing zone of Nigeria. Farmers in Ikire Osun state , Nigeria, dig a trench and bury the setts for suberization before planting Fig.

This practice is labour intensive but the setts with healed surfaces are as good as whole seed yams in terms of protection from fungal infections. In addition to whole seed tubers produced by double harvesting, some varieties produce 1—3 small tubers together with a large ware tuber that is used for food.

The small tubers are sorted and reserved for planting Fig. The seed sized tubers produced from a ware crop are the reason for the age long custom of using mainly farmer-saved seed in yam production. In this situation, farmers do not consider seed yam as a cost element in yam cultivation and are reluctant to adopt any method to increase seed production or improve their production practices. Small tubers should be used with caution as their size could be due to disease, especially of viral origin which is a major cause of seed degradation.

Due to the high cost of seed tubers, most yam farmers will not contemplate roguing. Where diseased plants are not rogued, it is not possible to distinguish diseased and healthy tubers at harvest because viral symptoms are not visible on yam tubers. In varieties with multiple tubers, the small tuber is reserved for seed while the big tuber is used for food.

The major aim of the technique is to increase the quantity and quality of seed tubers available to farmers. This development was based on the principle that any section of the tuber is capable of developing buds and sprouting provided it has a portion of the periderm Onwueme The 25 g recommendation was meant to be a compromise between the competing requirements of maximising setts from a single tuber and the need for a reasonable proportion of seed yams in the yield Kalu et al.

While there is much variation in the response of D. However, Okoli and Akoroda noted that there is wastage of edible tubers being used for planting, as 5—30 g setts could produce the recommended seed yam sizes of — g Akoroda a ; Onwueme and Charles Even 30 g setts of 5 mm thickness which are normally discarded as yam peels, yield mean tuber weights above g Aighewi The freshly cut minisetts are treated in a suspension containing wood ash or fungicide and insecticide, and then spread out in light shade to dry for 1—2 days IITA Treatment of setts before planting is influenced by challenges of unavailability, quality and high cost of chemicals.

While the use of wood ash as a substitute for fungicide and insecticide has been recommended, its effectiveness has been variable Otoo Minisetts can be planted directly in the field on ridges at a depth of 9—12 cm with a plant spacing of 25—30 cm by cm 4 stands per m 2 when the rains are well established.

Otherwise they could be pre-sprouted in beds, baskets or boxes using top soil, saw dust, shredded coir or carbonated rice husk as media.

Sprouting and tuber yield of direct planted setts are strongly affected by variety Ayankanmi et al. The condition of the soil at the time of planting also affects the survival of propagules. Although the treated minisetts can be directly planted in the field, it is usually recommended that they are first pre-sprouted in a nursery before transplanting. Pre-sprouting in a medium free of pest and disease can help minisett survival, but it is more labour intensive Okoli and Akoroda When minisetts are pre-sprouted, there is a better crop establishment because only sprouted minisetts are transplanted to the field, and this can be timed for a period when the soil is sufficiently wet to support adequate growth.

With pre-sprouting, additional time and cost are required to check the minisetts at intervals and select those that have sprouted for transplanting. Despite advantages of the minisett technique which include fewer ware tubers being used as seed, faster rate of multiplication than with traditional methods, ease of operation as well as potential for production of better quality seed and mechanization, the level of adoption remains low.

Some factors responsible for this are the scarcity and high cost of complementary inputs as well as additional costs for cutting and treating minisetts Chikwendu et al. The minisett technique is meant to produce seed tubers, so its promotion should be directed to dedicated seed yam producers, who exist in only a few yam growing areas. In traditional systems, ware yam farmers will sell seed after their fields are planted and there is surplus, and will buy if there are unplanted mounds due to a shortage of planting material.

In seed yam production the prefix micro is used in relative terms comparing the normal size of about g to very small setts of 10 g or less.

According to Alvarez and Hahn , microsett propagation with the aid of phytohormones increased the multiplication ratio of the traditional system from to Compared to other systems, the microsett technique was ranked best with regards to the number and cost of mother tubers needed for seed yam production, and the rate of multiplication IITA Although enormous amounts of yam could be saved using microsetts, preparation of setts could be labour intensive. Farmers may not be able to handle the small setts conveniently, and not all varieties may be suitable for use with this technique.

Plant Tissue Culture PTC is the growth of small plant parts in a nutrient medium in laboratory containers such as test tubes to regenerate the complete plant plantlets. The practice is done in a controlled laboratory environment which is not susceptible to changing weather conditions, such that production cycles can be planned Yam and Arditti Clean, high quality and uniform plants can be produced from otherwise unclean mother plants.

It uses tissues, organs or groups of organs, such as uninodal cuttings from stem fragments Fig. Selected clones are cleaned from virus diseases through meristem culture combined with thermotherapy, and the regenerated plants are virus indexed Ng The negatively indexed plants are then grown under sterile conditions in artificial media containing growth substances such as sugars, vitamins, and plant growth regulators, and multiplied to reach target numbers.

Thereafter, they are acclimatized and grown in pots to maturity to give whole seed tubers of high quality after 5—6 months. Tissue and organ culture to produce seed yam: 1. Field plants; 2. Single nodes from the field for in vitro culture; 3. Batch of in vitro plantlets in test tubes; 4. In vitro plantlet. The risk of plant losses during acclimatisation and the long period required to produce a seed tuber from tissue-cultured plantlets inspired studies into in vitro tuber production in yams as done for potatoes.

Yam microtubers produced from in vitro plantlets were therefore proposed as alternative materials for propagation Balogun due to the reduced incidence of diseases, small size and ability to regenerate after dormancy break, by-passing the hardening rigours. However, applicability will depend on the ability of different genotypes to produce microtubers in vitro.

Balogun et al. Although in vitro microtuber production has been proposed as an alternative propagation material, some of them were too small and failed to sprout showing the need to control microtuber dormancy Balogun Tissue culture plays an important role in the production and international exchange of disease free planting materials of yams in the form of plantlets and potentially as microtubers, but it has some obvious limitations.

These include high costs, the need for skilled personnel and specialized equipment, and more crop cycles are required to produce large quantities of suitable seed size tubers for ware yam production.

Although the aseptic steps taken in tissue culture give a higher assurance of quality, reducing the frequency of microbial contamination of tissues can be challenging. There is also a risk of re-infection once the seeds leave the aseptic conditions of laboratories and are transferred to fields where there is high disease pressure. Recently, yam researchers in West Africa have been focusing on vine cuttings as an alternative to the use of tubers in seed yam production. Rooted vine cuttings of 20 cm length with 1 to 3-nodes Acha et al.

Vine cuttings for tuber production should be taken from healthy plants aged between 30 and 60 days after shoot emergence, and before tuber development starts Okonmah ; Kikuno et al.

Cuttings are rooted in a high humidity chamber or carbonized rice husk before transplanting into soil or planting directly in top soil in a garden Fig. Scientists at the International Institute of Tropical Agriculture in Nigeria, have produced seed yam by planting vine cuttings in vertical grow bags in the screenhouse Fig.

Black polythene bags are filled with soil, tied, and then hung to poles or ropes running across the top of the screenhouse. Depending on the size of the bags, holes are pierced through to allow planting of vine cuttings. Water is supplied to the plants through irrigation pipes or watering cans and minitubers are harvested when the plants senesce.

This innovation maximizes the use of space in seed production. Mini-tuber production from D. Freshly cut vines; 2. Vine cutting rooting after planting: 3. Tuberization of vine cutting; 4. Minitubers produced from vines. While varietal differences in the rooting of vines have been noted, Acha et al.

Cabanillas and Martin noted that using single node cuttings, multiplication of yams could be several hundred fold in 1 year. However, appropriate and cheap methods of large scale rooting of D. Maroya et al. A major advantage of this method of propagation is that the entire tuber is saved for food, thus improving the economic value of the crop.

Moreover, setts produced would be free of nematodes and soil-borne pathogens if a sterilized medium or pest-free soil is used for propagation. Large quantities of small size minitubers that are appropriate for international exchange of germplasm can be produced using vine cuttings, as well as normal seed size tubers for production of ware yam depending on the time of harvest of vines.

Aeroponics is a method of growing plants in a soilless environment with very little water Carter Techniques for growing plants without soil were first developed in the s by botanists who used primitive aeroponics to study plant root structure Barker Atomizing nozzles ensure the most effective delivery of nutrients, as they turn the water into a fine mist and plants absorb the nutrients through their roots by absorption of compounds through cell walls.

This was done using both pre-rooted and unrooted vine cuttings. One-node pre-rooted vines of approximately 2 months old, as well as two node vines freshly cut from yam seedlings were transplanted into aeroponics boxes established in a screenhouse Fig. The initial results of both pre-rooted vines and direct planted vines were impressive as plants continued growing normally with development of new roots and shoots.

Minitubers produced from an aeroponics system: 1. Two-node cutting prepared for planting; 2. Plants growing in the system; 3. Rooting and tuberization of cuttings; 4. Multiple tubers produced on a cutting; 5. Harvested tubers. The first setts of microtubers harvested after 4 months of growth ranged from 0. Some of the plants in the aeroponics system were still growing more than 14 months after planting. When planted in soil, yam plants usually grow for 7—10 months before they senesce.

The type of nutrient solution ammonium phosphate 1. All the bulbils produced by D. Although it is too early to conclude on the rate of seed yam multiplication in aeroponics, it has been noted that the system can spectacularly improve seed yam propagation rates and quality of seed tubers, as the plants grown from tubers produced in the aeroponics system were assessed to be much cleaner healthier than those from traditional methods of production Maroya et al.

There is also the advantage of making several harvests of tubers from the same plant over an extended period of growth. The aeroponics system is not meant for direct use by farmers, it is planned to be useful in the formal seed yam system for pre-basic and basic seed production. The full potential and shortcomings of seed yam production by aeroponics will only be determined after a great deal more research on the system, including cost of production, has been carried out.

Bulbils on D. A bioreactor is an enclosed, sterile environment which is provided with inlets and outlets for air flow under pressure and utilizes liquid medium Watt It is an advanced tissue culture technology used for differentiated plant tissues. For a long time, bioreactors had been used in scaling up the production of plant secondary metabolites, including those that are of medicinal or health value to humans, using cell suspensions.

Different designs of TIBs exist, but most common are the Twin Flask types, having two containers, one for the medium and the other for the cultures Adelberg and Simpson This type of TIBs was established at IITA Ibadan, Nigeria to optimize protocols for efficient acclimatization of plantlets from tissue culture, automate micropropagation, and scale-up and enhance microtuber production Fig.

The plant tissues, single node cuttings were immersed in the medium in a timed manner, in terms of frequency and duration of immersion in liquid nutrient to allow for aeration.

In TIBs, growth is enhanced compared to tissue culture Escalona as immersion in the liquid medium is not continuous. By using TIBs for yam propagation both plantlet and microtuber production has been reported, although sprouting was greater with larger microtubers of D.

In both conventional tissue culture and the TIBs, plant tissues are fed a ready-made carbon source which makes the process heterotrophic. The ready-made carbon source e. Photoautotrophic micropropagation is now being advocated as little or no sucrose is used, in addition to better aeration achieved in TIBs.

Larger vegetative structures, such as tubers, can be obtained when plants are grown in TIBs, but photoautotrophically. In the latter, sucrose is partially or completely replaced with carbon dioxide Xiao and Kozai ; Curtis a , b. This imitates a natural field environment with little or no contamination and high yields.

This suggests that even larger microtubers can be produced and planted directly in the field. However, it will be necessary to standardize protocols for direct field planting of D. Advantages of TIBs include faster growth and acclimatization of plantlets due to more vigorous plantlets which are better able to withstand the shock of transplanting.

The implication of this is more clean seed of yam in the shortest possible time. However, a major disadvantage of TIBs is the cost of investment and that of the seeds produced using the technology. Although the seeds are premium, there is a limit to the unit cost for it to compete well. Therefore, low-cost technologies for photoautotrophic bioreactor systems are being explored as has been done for cocoa Curtis ; Shaw In the past there were difficulties in germinating yam seeds due to a failure to recognize their dormancy period, and because many seeds lack well developed embryos and endosperms Sadik and Okereke Efforts to improve D.

Some of these problems could be resolved by using varieties which naturally flower freely and are fertile, together with having a good knowledge of the combining ability of parents. Among the different methods of seed yam production used by Alvarez and Hahn , botanic seeds Fig. The use of botanic seeds for large-scale seed yam production would save the tubers for food, and greatly reduce the risk of tuber-borne diseases.

Botanic seeds provide a wider scope for crop improvement and seed handling while storage would be less cumbersome. However, the problems envisaged in this method of production could be the wide variation in seedling tuber size, colour, shape and quality as yam is an out crossing species.

The need for horticultural expertise, insufficient information on nursery practices, increase in labour input, a longer season to attain maximum yield or appropriate seed tuber size are other issues that could hinder large scale use of botanic yam seed.

All the technologies described above should have different users based on their respective interests and expertise. Irrespective of the propagation technique used, it is necessary to determine the attributes of the products in terms of quality, yield numbers versus weight , percentage survival after planting, cost, and multiplication ratio per unit time in a particular agro-economy when deciding the technology to adopt Balogun and Gueye A major factor determining the quality of seed yam is the presence or absence of virus.

Being vegetatively propagated, any virus in the source material will be multiplied in the field, and this has been a major challenge in the use of farmer-saved seed yam. Table 1 gives a summary of some characteristics of various seed yam production methods. The table does not attempt to make a thorough comparison because several other factors not mentioned also affect the product from different systems.

For example, different methods will require different periods of growth and cycles of production to obtain the seed size needed to produce ware yam. Often the yield is less, the tubers are much too small and of bad quality and contain a poison called dioscorine. For all these reasons, it is better to propagate by cuttings. But here care is needed Take cuttings from ripe tubers, and not from the aerial stems, as is done with cassava.

These root cuttings make plants which are like the parent plant, and give good yields. For the cuttings use pieces of tuber or small whole tubers. To get regular sprouting and good yields, the cuttings "whether whole tubers or pieces should weigh between and grammes. The amount of yams planted represents a considerable part about a quarter of the harvest. That much of the harvest must be set aside and well stored for use in planting later. Plant only fully ripe tubers.