SIRDC Releases Three New Maize Hybrids

The Scientific and Industrial Research and Development Centre (SIRDC) is pleased to introduce onto the market SIRDAMAIZE 115, SIRDAMAIZE 117 and SIRDAMAIZE 119, a follow up to the successful drought tolerant SIRDAMAIZE 113. The new varieties will be available on the market in the 2017/2018 summer cropping season.

Maize production in Zimbabwe is being negatively affected by drought, diseases and pests as well as poor soil fertility. In light of this, SIRDC and its research partners have developed three maize hybrids that have enhanced drought tolerance, nutrient use efficiency and disease resistance.

The new varieties have unique characteristics that give them a competitive advantage over other varieties in the same category currently on the market. These maize hybrids are highly suitable for the developing regions of the world, particularly the sub-Saharan Africa, where drought and low soil fertility are major impediments to the attainment of high yields.

Currently Zimbabwe is experiencing one of the worst food shortages due to the failure of the maize crop in the 2015/16 farming season. While several efforts are being made by government to ensure food security, the use of adapted and climate smart maize varieties forms the basis of increased maize productivity in the future. Therefore these new maize varieties could not have come at a better time.

The new maize hybrids were developed through marker assisted selection and classical breeding techniques. The hybrids went through rigorous testing for three seasons. The tests and trials were done in Zimbabwe and at sites within Southern Africa using the available network of research stations. The new varieties were evaluated in regional trials and compared to already established maize hybrids in the region.

Tried and tested advanced scientific procedures were employed to compare these hybrids with similar intermediate to late maturing maize hybrids available on the market. In the 2011/2012 season, the evaluation was done against 49 hybrids. In the 2012/13 agricultural season, the trials had 66 hybrids while 60 hybrids were evaluated during the 2013/14 summer season.

In Zimbabwe, the hybrids were tested under different management conditions namely; optimum conditions (under rain-fed conditions with supplementary irrigation, when necessary, and recommended quantities of fertilizers being applied), high plant density (1.5 of the normal maize plant population density), low plant density (trial evaluated under 0.5 of normal plant population density), random stress (trial grown under rain fed conditions in the rainy season with no supplementary irrigation, and recommended quantities of fertilizers applied), low soil nitrogen (trial grown in soil depleted of nitrogen, recommended phosphorus and potassium applied), low soil pH (trial grown under rain-fed conditions in fields that are known to be low in soil pH based on soil analysis results), maize streak virus infestation (trial grown under rain-fed conditions with supplementary irrigation when necessary, with recommended fertilizers applied, at 4 leaf stages trials were infested with maize streak virus carrying leafhoppers to transmit the disease), sandy soil (trial evaluated in sandy soil which have high leaching, low soil pH and low nutrient status).

In addition to the various management conditions, the varieties were also tested under different locations and environmental conditions. The testing sites that were used in Zimbabwe include Art Farm, Rattary Arnold Research Station, Agriseeds Farm, Devonia, Kaguvi, Chibero, Shamva Experimental Station, International Maize and Wheat Improvement Centre (CIMMYT), Gwebi, Chisumbanje Experimental Station, Kadoma Research Station, Harare Research Station, Chiredzi Research Station, Save Valley Experimental Station, Makoholi Experimental Station, Marondera Research Station, Harare Research Station and SIRDC Farm.

The regional testing sites were in the following countries: Malawi, South Africa, Zambia, the Democratic Republic of Congo and Mozambique. The testing environments in Southern Africa were classified into different agro-ecological regions.

On-farm trials were conducted during the 2013/14 summer season, where nine farmers from three districts of Zimbabwe, namely; Murehwa, Mutoko and Bikita participated. Data analysis was done by SIRDC scientists using field books at individual and across sites and the highly performing hybrids were selected.

It was found out that SIRDAMAIZE 115, SIRDAMAIZE 117 and SIRDAMAIZE 119 consistently outperformed their competitors yield, drought and disease tolerance as outline below for each variety. These maize varieties are distinct, uniform and stable as evaluated by Seed Services of Zimbabwe, which is under the Department of Research and Specialist Services (DR&SS) of the Ministry of Agriculture, Mechanisation and Irrigation Development.

A brief outline of each of the varieties is as follows:

SIRDAMAIZE 115

SIRDAMAIZE 115 is a medium maturing white, semi flint three way hybrid with a high yield potential in both optimum and stress prone environments. It attains mid pollen shedding in 66 - 69 days and requires 132 days to reach physiological maturity. The variety has good tolerance to gray leaf spot (caused by Cercosporazeae-maydis), maize streak virus, Northern leaf blight (caused by Exserohilum turcicum) and common rust (caused by Puccinia sorghi).

The yield potential of SIRDAMAIZE 115 is 12.35 t/ha and that was realised at Art Farm during the 2013/14 summer season. This hybrid is tolerant to drought stress that occurs during flowering where it still yields 1.05 t/ha while similar hybrids on the market yield an average of 0.23 t/ha.

These grain yields were realised under managed drought stress in 2013 winter trials at Save Valley Experimental Station. Under random stress sites, this hybrid had a grain yield of 5.84 t/ha at Kadoma Research Station during the 2013/14 summer season. SIRDAMAIZE 115 is tolerant to low soil nitrogen with a significantly high grain yield potential of 3.75 t/ha.

The hybrid is also tolerant to maize streak virus where under inoculation it was able to produce 7.51 t/ha whereas other hybrids on the market produced 4.01 t/ha. SIRDAMAIZE 115 also has lower maize streak virus score of 2.3 under inoculation trials using a score of 1 to 5 (where 1 indicates clean, no infection and 5 severely diseased). This is a highly desirable score as it means the maize crop does not suffer high losses due to virus infestation.

Gray leaf spot and Northern leaf blight are common diseases in high potential sites. Under the inoculation trials SIRDAMAIZE 115 scored 1.8 and 3.1, respectively under the same scale of 1 to 5. The tolerance to these diseases was further observed by the highest yield of 7.46 t/ha in the trial. SIRDAMAIZE 115 has shown tolerance to low soil pH, as observed by significantly higher grain yields of 2.31 t/ha.

SIRDAMAIZE 115 has high grain yields of 8.82 t/ha and 6.40 t/ha under low density plant populations and conservation agriculture trials, respectively. Under sandy soil and striga, commonly known as Witch weed, infestation this hybrid has grain yields of 3.08 t/ha and 4.49 t/ha, respectively. Under on-farm conditions SIRDAMAIZE 115 had a grain yield of 2.17 t/ha, while similar hybrids on the market had grain yields of 2.12 t/ha and 1.52 t/ha, respectively.

The mean and stability analysis showed that SIRDAMAIZE 115 has the highest grain yield across the test environments and is stable across the environments. Generally this hybrid can be grown in high potential sites namely NR II, and low potential regions NR III, and IV.

SIRDAMAIZE 117

SIRDAMAIZE 117 is a drought tolerant variety with a short anthesis-silking interval that counters delayed silking under water stress conditions. It has tolerance to several diseases namely; Gray leaf spot, maize streak virus, Leaf blight and Common rust. It is an intermediate maturing white maize hybrid. The variety has a slight degree of zigzag while the curvature of the blade is straight. The anthocyanins colouration of the base of blade is strong whilst the colouration of the glume excluding the base is medium. The silks on the other hand have a medium anthocyanin colouration.

SIRDAMAIZE 117 has a yield potential of up to 13.63 t/ha under optimum conditions. The variety has relatively good drought tolerance as indicated by yield of 2.36 t/ha which was obtained at Kadoma Research Station which was comparative to drought tolerant varieties on the market. At Rattray Arnold site, the variety had a yield of 3.26 t/ha and out-yielded similar commercial varieties under low nitrogen.

At CIMMYT Harare under low phosphorus it had a yield of 8.69 t/ha and out-yielded all the local check varieties it was compared to. At the CIMMYT Harare site under maize streak virus infestation the variety showed excellent maize streak virus tolerance as it obtained high yield of 8.85 t/ha which out-yielded all the check varieties.

SIRDAMAIZE 119

SIRDAMAIZE 119 is an early to intermediate maturing white maize hybrid. The hybrid has shown to be high yielding under low nitrogen and drought stress conditions and has good tolerance to foliar diseases such as Gray leaf spot, Maize streak virus and Leaf blight. Anthesis period ranges from 66 to 75.8 days.

SIRDAMAIZE 119 has a maximum yield potential of 11.39 t/ha under optimum conditions, 7.82 t/ha under high density, 7.09 t/ha under low density, 7.44 t/ha under disease (artificial Gray leaf spot and Northern leaf blight), 4.31 t/ha under random stress, 2.56 t/ha under low soil nitrogen, 7.58 t/ha under low phosphorus, 7.18 t/ha under maize streak virus infested conditions and 6.24 t/ha under striga infested growing conditions.

The potential yield was higher than that of all the check varieties. SIRDAMAIZE 119 has significantly lower disease scores compared to the check varieties, which means it is more tolerant to the diseases. SIRDAMAIZE 119 has disease scores of 1 for MSV, 1.6 for Common rust, 2.2 for Leaf blight and 1.6 for Gray leaf spot. SIRDAMAIZE 119 yields significantly higher than other maize varieties under managed drought stress conditions. The anthesis period for SIRDAMAIZE 119 ranges from 66 to 75.8 days.

SIRDAMAIZE 119 is therefore a low nitrogen, and drought tolerant maize hybrid with good tolerance to Maize streak virus, Gray leaf spot, Common rust and Northern leaf blight. The hybrid can be grown in Zimbabwe in locations that fall under the agro ecological zones II to IV and also under low fertilizer use.

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