Bio

DR. KANYA JAMES IRERI CV

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Publications


2014

Njiruh, PN, Kanya JI, Kimani, P.M; Kimani JM, Wanjogu RK, Kariuki SN.  2014.  Segregation distortion of anthocyanin morphological marker in F2 population of cross between basmati and environment genic male sterile rice line. International Journal of Agronomy and Agricultural Research . 3:43-52.

2013

Njiruh, PN, Kanya JI, Kimani, P.M; Kimani JM, Wanjogu RK.  2013.  Production of hybrid Basmati rice in Kenya: progress and challenges. International Journal of Innovations in Bio-Sciences. 3(4):115-124.
J.I., K, P.N N, Kimani J.N., R.K. W, Njau KS.  2013.  Evaluation of Photoperiod and Thermosensitive Genic Male Sterile Lines For Hybrid Rice Seeds Production in Kenya. Abstract

Photo–thermo-sensitive genic male sterile (P(T)GMS) rice is a new hybrid rice technology that uses prolonged
light length and high temperatures to induce sterility. This technology is being introduced in Kenya but such
growth conditions are lacking in the tropics. To overcome this, we grew P(T)GMS under greenhouse conditions
where day light length was prolonged to 14 hrs using solar illumination and day and night temperatures were
maintained above 36Cº and 24ºC respectively. Sterility of P(T)GMS was determined by the level of abortive
pollen and seed set rates. Hybrid seeds were produced by crossing three P(T)GMS lines (V1PGM, V2TGM and
V3PGM) as female lines with Basmati 370 and Basmati 217 varieties as pollen donors. Under long and normal
day lengths and high temperatures, pollen sterility ranged from 99-100% but no seeds were set in PGMS lines.
However, TGMS recorded 3% and 2% seed set under similar conditions. Under natural conditions both PGMS
and TGMS reverted to fertility. Agronomic evaluation showed outstanding (P<0.01) performance of hybrids over
parents in flag leaf length (V2370; 35.8 cm), panicle exsertion (V2217; 8cm) and shorter flowering time (V3217;
85 days) under greenhouse conditions while flag leaf width (V1370; 1.48 cm) and tillering (100) performed better
under natural conditions. Percentage seed set positively correlated with flag leaf related traits and flowering days
but negatively correlated with panicle length, panicle exsertion and tillering. We conclude that the P(T)GMS lines
are adaptable for hybrid rice seed production in Kenya but there is need to review the P(T)GMS lines’ background
so as to minimize incompatibility in hybrids.Key words: Oryza sativa, Basmati, PGMS/TGMS, seed technology, pollen sterility.

2012

Kanya, JI, Kinyamario JI, Amugune ON, Hauser PT.  2012.  Hybridization Potential Between Cultivated Rice Oryza sativa and African Wild Rice Oryza longistaminata. International Journal of agricultural research. 7(6):291-302.
Nthakanio, NP, Ireri KJ, Munji. KJ, Raphael W.  2012.  Adaptability of PGMS and TGMS rice lines for hybrid rice seed production in Kenya..
P.N, N, J.I. K, J.N K, R.K. W.  2012.  Use of Anthocyanin morphological markers to select hybrids from non-hybrids Basmati lines. Abstract

Basmati rice (Oryza sativa L.) is preferred by consumers over other varieties because of its aroma and good cooking traits. However, its yield is genetically low compared to other pure bred lines. To increase yield of Basmati per hectare, it has become necessary to adopt hybrid rice technology that has been reported to increase yield by up to 30% above pure dwarf lines. Photoperiod-sensitive genic male sterile (PGMS) and Thermosensitive genic male sterile (TGMS) rice lines contain genes that confer male sterility under long day light-length and high temperature growth conditions, respectively. Pollination of these lines, in their male sterile period, with a viable male parent pollen produce hybrid seeds. The problem of using PGMS or TGMS is that in the tropics, day-light length is 12hours and diurnal temperature range is high, making induction of complete male-sterility in these lines difficult. The result is contamination of hybrid seeds with self-bred pure line seeds. The objective of this research work was to produce pure hybrid Basmati seeds. Hypothesis to be tested is that anthocyanin markers can be used to differentiate hybrid F1s from pure inbred seedlings. This tool can be used in selection of Basmati hybrid seedlings free from contamination with self-bred parents before transplanting and therefore save on the associated losses. The F1 seeds from a cross between PGMS or TGMS and Basmati were sown in greenhouse at KARI Mwea- Kimbibi station. Hybrid seeds were scored for anthocynanin morphological marker, by observation, to differentiate them from the pure bred lines. All hybrids involving Basmati370 and Basmati217 had very conspicuous incidence of anthocyanin which made them distinct from the parents. The conclusion is that anthocyanin can be used as a marker to separate F1 hybrid plants from the parents.

Key words: Anthocyanins, Morphological marker, Basmati, Hybrid rice seed

Njiru P.N., J.I K, Kimani J.N., R.K W.  2012.  Establishing a “Microbial-Plant” as means to control rice blast disease.

2009

J.I., K, J.I K, O.N A, P.T H.  2009.  Dispersal distance of rice (Oryza Sativa L.) pollen at the Tana River delta in the coast province, Kenya. African Journal of Biotechnology. 8(10):2265-2270..: African Meteorological Society Abstract

Rice is a staple food in Kenya and its production needs to be increased. Genetically modified (GM) rice
may be a solution, but before it can be introduced, potential ecological impacts, such as pollen
mediated gene flow from GM rice to non-GM rice or to its wild indigenous relatives, need to be
understood. Pollen dispersal in rice (Oryza sativa) was studied in the Tana River district in the coast
province of Kenya. O. sativa seedlings were planted in a 50 m diameter circular experimental design.
Pollen traps (glass slides coated by vaseline attached to a board) were used to measure pollen flow at 2
heights and at increasing distances from the source plot. Pollen dispersal decreased rapidly with
increasing distance from the pollen source up to 250 m, no pollen was found at 300 m. There was a
significant (P < 0.05) difference in pollen dispersal in different directions, which correlated with the
prevailing wind direction (south, occasionally east). Effect on wind speed and humidity could not be
evaluated as they were relatively stable during the sampling period. No overall difference (P > 0.05) in
pollen count between upper and lower pollen traps. The highest daily pollen count was observed
between 11:00 am and 12:00 noon, and at a narrow range of temperatures 28 ± 2ºC. On the basis of
these data, an adequate isolation distance of more than 250 m should be considered to minimize
chances of gene flow from transgenic rice to conventional or wild rices.

2004

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