J Food Nutr Agric 2018: 1(1) https://www.phoenixpub.org/journals/index.php/jfna 30 Journal of Food, Nutrition and Agriculture, 2018: 1(1) 30−34 http://dx.doi.org/10.21839/jfna.2018.v1i1.205 ISSN 2616-6550/ © 2018 Phoenix Research Publishers Research Article Evaluation of yellow maize inbred lines for maturity and grain yield related traits using line×tester analysis Farman Ullah 1 , Fawad Ali 2 , Abdus Salam 2 , Muhammad Siddique Afridi 2 ٭, Hidayat ur Rahman 1 1 Department of Plant Breeding and Genetics, The University of Agriculture, Peshawar-Pakistan 2 Department of Plant Sciences, Quaid-i-Azam University, Islamabad−45320, Pakistan (Received: 02-06-2018; Revised 05-10-2018; Accepted 06-10-2018; Published Online 17-10-2018) ٭Corresponding author (E-mail: msafridi@bs.qau.edu.pk) Abstract Thirty yellow maize inbred lines were selected from different source populations and planted in isolation with common male testers (YD-2 and YD-4) in 1:4:1 ratio at Cereal Crop Research Institute (CCRI) Pirsabak, Nowshera during spring-2014 (season–I). On the bases of best seed setting and other important traits, eighteen test-crosses were selected using line × tester approach. The developed 18 test-crosses, nine parental lines and two testers along with two check cultivars (Sarhad Yellow and CS2Y10) were grown in summer season-2014 (July – November) using two replications.Data were collected on various maturities and yield related traits via; days to pollen shedding, silking, ear height, plant height, 100-kernel weight, kernel row ear -1 and grain yield. Significant differences were observed among test-crosses for yield related traits mainly 100-kernel weight and grain yield. L-9 using YD-4 as a tester revealed minimum days to pollen shedding (50.5 days) and days to silking (52.5 days). L-3 using YD-2 as a tester recorded maximum plant height while, L-9 using YD-4 as a tester obtained maximum ear height and length. L-9 using YD-4 as a tester revealed high 100-kernel weight, grain yield and high GCA effect, while L- 8 using YD-4 as a tester recorded high SCA effect for 100-kernel weight. L-9 exhibited high GCA effect for grain yield while, high SCA effect was obtained for L-2 using tester (YD-2). L-9 using tester YD-4 revealed maximum mid-parent and best-parent heterosis for ear length and grain yield. For maximum traits, L-9 was the best combiner followed by L-3 and L-6 using the same tester (YD-4) under conducted study. Keywords: General combining ability, Heterosis, Maize, Specific combining ability, Tester analysis Introduction Maize (Zea mays L.) is grown worldwide and used as a primary staple diet in many developing countries (Morris, 1999). During 2013, total maize production was 950 million tons showing an increase of 9% compared to previous year- 2012 reported by Brandt (2013). According to International Institute of Tropical Agriculture, Hahn et al. (1989), total world production of maize was 785 million tons. United States contributes 42% to the total maize production worldwide, thus stands for the leading producer. Maize is the 3 rd most developed crop after wheat and rice. Maize was cultivated on 1139.4 thousand hectares acreages for production with total yield of 4997.1 thousand tones and 4385.7 kg ha -1 , respectively in Pakistan (PBS, 2012-2013). Maize is a consistent crop in the cropping pattern and also used as a primary food for poor resource farmers in Khyber Pakhtunkhwa (Khan et al., 2003). Yellow maize is more valuable than white maize to feed animals because of containing huge amount of Vitamin-A (Morrison, 1936). The breeding strategies used in maize are normally characterized by increasing of genetic diversity in the pool of germplasm (Lee, 1998). Heterosis is an important phenomenon which leads to the development of hybrids showing desired superiority in maturity, disease resistance and yield contributing traits over the parental inbreed lines (Lippman and Zamir, 2007). Combining ability and heterosis computations are helpful for the development of economical and sustainable maize hybrids and cultivars (Krivanek et al., 2007). Evidence on combining ability and heterosіs among maize germplasm are necessary to increase the efficacy of hybrid development. The significance of a "good tester" depends upon the breeders objectives. Breeders study the specific and general combining ability of various lines and also the gene effects by using line × tester analysis. The information about mode of inheritance and genetic arrangement of different characters helps breeders to employ proper breeding techniques for improvement in crops (Kiani et al., 2007). The easiest and most accurate approach towards screening of large number of inbred lines and parental genotypes are line × tester analysis and combining ability (Kempthorne, 1957). Materials and Methods Two experiments in two consecutive seasons were conducted at Cereal Crop Research Institute (CCRI) Pirsabak, Nowshera using RCB Design in 2014. During spring season-2014 (February – June), 30 yellow inbred lines from different source populations were planted in isolation with common male testers, YD-2 and YD-4 in 1:4:1 ratio each with a row length of 3m, plant to plant distance of 25cm and 75cm space between the rows to facilitate easy crossing and to manage the breeding material easily and carefully. The developed 18 test- crosses, nine parental lines and two testers along with two check cultivars (Sarhad Yellow and CS2Y10) were grown in summer season-2014 (July – November) using two replications. Each plot consists of two rows having row to row and plant to plant distance of 75cm and 25cm respectively. Data were taken on days to pollen shedding, to silking, ear height, plant height, 100-kernel weight, kernel rows ear -1 and