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Development
of stress –tolerant maize varieties in Uganda: special case for LP 16
(Longe 4)
J. Imanywoha,
D.T. Kyetere, G. Bigirwa, J.T. Kikafunda, T.M. Kalule, K. Pixley &
A. Nakayima.
Farmers
in Uganda are becoming increasingly dependant on maize for both food and
cash crop. This is happening at a time when crop failures are on
increase. In western Uganda, crop failures are often experienced in the
first season while in the East, they commonly occur in the second
season. A call from farmers and other stalkholders for a short-term
maize variety was registered in 1994, a drought year.
In response, open pollinated varieties from CIMMYT and IITA were
introduced and evaluated for earlieness and adaptability, however, none
of them was found suitable. Then a breeding program to develop such a
variety was initiated by crossing the maize varieties: Longe 1, Pool
16SR, Pop 43SR, ZM 607 and Pop 49SR. Their F1 progenies were tested in
four locations in Uganda. Based on yield, days to 50% silk, reaction to
gray leaf spot (GLS) and turcicum leaf blight (TLB), a cross between
Longe 1 and Pool 16 SR was selected for improvement. Using Longe 1 as
the seed parent, a fresh cross between the two parents was done and a
total of 152 ears were obtained. Instead
of bulking seed from all the ears and planting together to random mate,
each ear was planted to a row. Selection based on reaction to TLB was
done and bulk sibing the selected rows conducted. At
physiological maturity, 49 families were selected based on their
reaction to GLS from which a total of 162 ears were selected. These were
organized in a trial as families and evaluated in three locations. Forty
families with yields similar to Longe 1 but silking 5-7 days earlier
were selected to constitute the released variety LP16 now known as
“Longe 4”. In terms of yield, Longe 4 gave 2490-5278 kg/ha, which
were similar to Longe 1 but significantly higher than Katumani.
Additionally, Longe 4 had scores of 2.5 for TLB, 3.5 for GLS and 2.8 for
MSV on 1-5 severity scale. Farmers preferred Longe 4 for its earliness,
drought tolerance and high yield. The same variety is a candidate for
release in Tanzania and Kenya.
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