The advent of Crop Intensification Program (CIP) in 2007 made maize crop a major national food crop and contributor to food security and enhancement of national economy where maize national production evolved from 101,659 t in 2007 to 667,834 t in 2013.

The development of maize cropping systems coincided with the introduction of hybrid maize varieties. Before 2007, maize was a marginal crop and its cropping systems was limited to volcanic highlands and some parts of the country Umutara region. The maize varieties were made by several Open Pollinated Varieties.

The use of maize hybrid still low: 50 % for large scale farmers, 15 % for small scale farmers and on average less than 30 %. Currently, the source of hybrid maize varieties is exclusively through seed importations with negative implications such as introduction of new pests that were previously unknown in the country; varieties used for seed production are not well adapted to the local conditions; the country loose a number of jobs in hybrid seed production; the development of skills in maize hybrid seed production is lacking and the importation of seed is very costly.

The hybrid seed has been so far mainly imported from international seed companies such as Seed Co Ltd, Kenya Seed Company Ltd and PANNAR Seed.

The hybrid maize variety requires the availability of parent inbred lines. Inbred lines are obtained after several generations of self-pollination through pedigree breeding. The cross between two unrelated inbred lines gives a hybrid variety.

The types of hybrid maize varieties under cultivation are Single Cross Hybrids (SCH), Three Way Cross Hybrids (TWCH) and Double Cross Hybrids (DCH). The SCH (A x B) is obtained by crossing two inbred lines, the TWCH [(AxB)xC] is obtained by crossing a SCH and an inbred line and a DCH[(AxB)x(CxD)] is obtained by crossing two SCHs.

The SCHs are uniform high yielding than TWCH and DCH, but the main problem is the seed production because the female parent is an inbred line and hence seed are not enough to meet the cost involved. Hence developed countries use SCHs while developing countries use TWCHS.

The program of developing Rwandan inbred lines started in the year 2009 using two sources: development of the parent inbred lines from Open Pollinated Varieties under cultivation and introduction of inbred lines from CIMMYT.

Only CIMMYT’s inbred lines are publically available because it is a CGIAR center. Otherwise no other seed company or organization can make available its inbred lines. In the financial year 2015-2016, RAB Scientists made available nine maize hybrid varieties.

The seed production has started in collaboration with local seed companies with the objective of reducing the needs in hybrid maize seed importation by 60 % for the financial year 2018-2019 and by 100 % for the financial year 2019-2020.

1. RHM104: It has drought tolerance traits and adapted to mid altitudes from 900 masl up to 1800 masl. It yielded on average 7.89 t/ha in multi-site trials conducted in four sites: Rubona (Huye), Cyabayaga (Nyagatare), Karama (Bugesera) and Bugarama (Rusizi) in 2013A, 2013 B and 2014 A seasons.

Currently, basic seed are being produced by RAB-Seed Unit (Gasabo, Rubungo, 4.2 ha) and Win Win Agri Tech Ltd (Ngoma, Karembo, 2 ha). Furthermore, RISCO is producing certified seed in and has planted 10 ha (Nyagatare, Karangazi, Gabiro). He is expected to harvest at least 30 t of certified seeds in February 2017.

2. RHM1407: It is adapted to mid altitudes from 900 masl to 1800 masl. The hybrid was evaluated under artificial and natural inoculation for Maize Lethal Necrosis (MLN) disease and it was proven to possess MLN tolerance. The hybrid was evaluated in four sites: Rubona (Huye), Cyabayaga (Nyagatare), Karama (Bugesera) and Bugarama (Rusizi) in 2015 A, 2015 B and 2016 A seasons. It yielded on average 7.87 t/ha on average. Currently the basic seed is being produced by RAB-Seed Unit (Rubilizi, 2 ha), SOZO Company (Gasabo, Kimironko, Kibagabaga 3.5 ha) and EMFAGM Ltd (Gatsibo, Rwimbogo 2.5 ha).

3. RHT132: It is adapted to altitudes from 1400 to 2000 masl (transitional zones). The hybrid was evaluated under artificial and natural inoculation for Maize Lethal Necrosis (MLN) disease and it was proven to possess MLN tolerance. It was evaluated at Rubona, Musanze, Nyagatare and Karama in 2013 A, 2013 B and 2014 A and yield on average 7.89 t/ha. The basic seed is being produced by RAB-Cereal Program (Rubona, Huye under 1 ha and Cyabayaga, Nyagatare).

4. RHM1409: It is adapted to mid-altitudes from 900 masl to 1700 masl. It has been evaluated under MLN artificial and natural inoculations and was found to be mild resistant to MLN disease. The hybrid was evaluated in four sites: Rubona, Nyagatare-Cyabayaga, Karama and Bugarama in 2015A, 2015 B and 2016 A. It yielded on average 8.67 t/ha on average. The basic seed is being produced by RAB-Cereal Program.

5. RHM1402: It is adapted to mid-altitudes from 900 masl to 1800 masl. The hybrid was evaluated in four sites: Rubona, Nyagatare-Cyabayaga, Karama and Bugarama in 2015 B and 2016 A. It yielded on average 8.59 t/ha on average. No seed company has taken the hybrid for seed production. The basic seed is being produced by RAB-Cereal Program.

6. RHMM111: It is specifically adapted to semi-moist mid altitudes. It is an extra-early maturing variety. It matures on average in 100 days. The hybrid variety was evaluated in four sites: Rubona, Nyagatare-Cyabayaga, Karama and Bugarama in 2015A, 2015 B and 2016 A. It yielded on average 6.16 t/ha on average. The seed production is at pre-basic level being conducted by RAB-Cereal Program level and Seeds of Trust-Rwanda Ltd.

7. RHMMM113: It is a t adapted to altitudes from 900 masl to 1700 masl. It is an early maturing variety and matures on average in 110 days. The hybrid variety was evaluated in four sites: Rubona, Nyagatare-Cyabayaga, Karama and Bugarama in 2015A, 2015 B and 2016 A. It yielded on average 8.23 t/ha on average. The seed production is at pre-basic level and it is being conducted by RAB-Cereal Program level and Seeds of Trust-Rwanda Company Ltd. No seed company has taken the hybrid for seed production.

8- RHMH1520 is adapted to highlands ecology at altitudes >1800 masl. It has been tested in multilocation trials at Rwerere, Musanze and Rubona in 2015 and 2016. It had on average a grain yield of 7.8 t/ha. The basic seed production is being conducted by RAB-Cereal Program.

9. RHMH1521 is adapted to highlands ecology at altitudes>1800 masl. It has been tested in multi-location trials at Rwerere, Musanze and Rubona in 2015 and 2016. It had on average a grain yield of 7.6 t/ha. The basic seed is being produced by RAB-Seed Unit and RAB-Cereal Program.