New high yielding disese resistant dwarf papaya

Dr.Fredah Wanzala developed 4 new papaya hybrids that were dwarf,high yielding and resistant to viral diseases


She is probably one of the most resourceful people in the horticulture industry and especially when it comes to fruits. Her passion for fruits is undoubtful when she takes her time to explain all the protocols in breeding of the papaya fruit. Dr. Fredah Wanzala, the brains behind the transformation of papaya in Kenya, is a Lecture at Jomo Kenyatta University of Agriculture and Technology and a holder of Bachelor of Science in Horticulture from Egerton University, Master of Science (Horticulture) from University of Nairobi and a holder of PhD in Agricultural Science from the United Graduate School in Japan. When HortiNews catches up with her at her office in JKUAT, Dr. Fredah, who has tasked herself in elevating papaya by breeding to get the best products that will go to unprecedented records, looks so full of hope as she has already developed 4 varieties for Kenya that are resistant to viral diseases. She takes us through this journey of her love for fruits.

Why specialize in fruits?

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Fruits are very special. When they ripen you eat them without even having them cooked as they are ready-to-eat. I developed interest in post-harvest handling while in university and that’s where my interest on fruits begun. This has given me the opportunity to contribute in the papaya industry in Kenya. Colored fruits like mango, avocado, ripe banana, papaya, passion fruit, watermelon among others are full of antioxidants which act as scavengers that destroy free radicals (by-products of body metabolism). Free radicals contribute to premature aging and degenerative diseases like cancer. Thus, fruits are of great value to our bodies.

Your journey with Papaya breeding.

After graduation with Masters degree, I was awarded a scholarship by the Japanese government to study for Doctor of philosophy (PhD). The objective of my PhD research was to develop pure breeding line for papaya through a technique called haploidy, i.e. the development of plants with a single set of chromosome.  In the process I came up with plants having 3 sets of chromosomes (triploids) at 75 percent and a very small percentage of other ploidy levels (haploid, diploid and tetraploid). Triploid papaya fruits were larger than their diploid counterparts and seedless. I could not continue with this research because I graduated and travelled back to Kenya. This gave me interest to carry out more research in papaya. I teamed up with other researchers in JKUAT and wrote a proposal that was funded by the government of Kenya through JKUAT in 2008 and later by Regional Universities Forum for Capacity Building in Agriculture (RUFORUM). Through this research, we developed 4 new papaya hybrids that were dwarf, high yielding and resistant to viral diseases.

How did you develop the hybrids?

We collected papaya germplasm from the main growing areas like Central, Coast, Eastern and Riftvalley and evaluated them at JKUAT for superior traits like high yields, dwarfness and resistance to viral diseases. We isolated superior breeding lines, carried out cross breeding followed by evaluation and confirmation of the hybrids at JKUAT.  We applied for plant breeders rights with Kenya Plant Heath Inspectorate Services (KEPHIS) and the 4 hybrids were gazetted in 2017 (gazette notice dated 17th November 2017) with no objections.

Where did you carry out evaluation trials for the new hybrids?

We carried out multi-locational trials in Mitunguu irrigation scheme and Nkubu in Meru County, KARLO, Mwea in Kirinyaga County as well as JKUAT. The quality of the fruits of all the four hybrids met and even exceeded international standards. Mitunguu Irrigation Scheme gave the best data with the sweetest papayas.

Are there best or natural ways of controlling pests in papaya?

Yes. I would recommend a concoction of hot pepper and Neem leaves (muarobaini).

Apart from Papaya fruits, are there other fruits you are interested on?

The Avocados. Currently there is a very high demand on this precious fruit and both the domestic and international markets are very demanding and I think it is the right time we start thinking about avocados because farmers have been doing it the wrong way with the international market putting very stringent measures in their markets for this produce. Hass and Fuerte varieties are the most common for the export market in Kenya with Hass variety being on demand but there is an assurance within the next 5 years the production for both will be 50-50. Avocados are the only crops that open flowers twice – the first time only the female parts are mature and receptive, while the male organs are mature and shed pollen when the flower opens the second time.

The differences between the two varieties.

Hass has a rough skin giving it a longer shelf life as compared to fuerte that has a thin skin. Hass is a regular bearer, while Fuerte is an alternate bearer. When Hass ripens the skin turn purple but fuerte remains green.

What is your take on avocado growing in Kenya?

Avocado fruits mature  6 to 8 months after flowering. The peak harvest season runs from March to July. During the month of September to March there are insufficient avocados in the farms therefore being low or off peak season. The country is not able to produce enough for the market and there is need to gear up and produce more that will make avocados become the leading exports for the country. This will not only bring more income to the farmers and the country through tax but also increase the GDP of the country. In Sub-saharan Africa, Kenya is the number one exporter of avocados. Kenya is hundred percent tropical and crops can be grown at any time, this is why everyone wants our avocados.

Are we doing it the right way?

Our farmers lack basic knowledge on growing avocados and a lot needs to be done since once you fail at the beginning which is by picking the wrong seedling and planting it the wrong way, one should not  expect much at the end of the day. They should be educated on getting the right seedlings and planting them the right way for them to get the best produce at the end. Scions for grafting the seedlings should be from mature trees. The seedling that develops into a fully grown tree should be fed with sufficient nutrients that contain Phosporus, Nitrogen and Potassium, sufficient ventilation and light penetration through pruning. Avocados cannot withstand water stress. It is also essential to do soil analysis before planting to determine the kind of nutrients required. Mature trees also need to get enough lighting when fruits start to form. A mature tree can produce about 1000 fruits in a year. Many Kenyans rely on rainfall for farming; the demand for seedlings is therefore high during rainy seasons.

Parting short……………………………….

We are yet to get funds to have the new papaya hybrids registered in Kenya. It has been a long journey and it is my hope we will get a donor to support this noble project to completion. Once the whole registration process is completed, we will quickly multiply the seedlings for farmers.  The new papaya hybrids are the legacy that I give the horticulture industry – being not only the first person to successfully breed papaya in Kenya, but also the first woman with a vision to transform the Kenyan papaya for better yields and quality.


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