Genetic Analysis of Maize (Zea mays L.) Genotypes for Baby Corn, Green Ear and Grain Yield  

Tajwar Izhar1 , M. Chakraborty2
Department of Plant Breeding and Genetics, Birsa Agricultural University, Ranchi -06 (Jharkhand), India
Author    Correspondence author
Maize Genomics and Genetics, 2014, Vol. 5, No. 1   doi: 10.5376/mgg.2014.05.0001
Received: 10 Dec., 2014    Accepted: 23 Dec., 2014    Published: 31 Dec., 2014
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This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:

Izhar and Chakraborty, 2014, Genetic Analysis of Maize (Zea mays L.) Genotypes for Baby Corn, Green Ear and Grain Yield, Maize Genomics and Genetics, Vol.5, No.1 1-6 (doi: 10.5376/mgg.2014.05.0001)

Abstract

Most maize cultivars have been developed for grain production. Considering the diversified uses of maize, interest has been demonstrated for the evaluation of maize hybrids with regard to their baby corn, green ear and grain yield production ability. In the present work seventeen corn cultivars were evaluated in the yield of baby corn, green ears and dry grains. Two experiments were carried out in the same season, in neighboring areas and managed in a similar way in Birsa Agricultural University, Ranchi, Jharkhand, India in a randomized blocks design with three replicates. Baby corn yield was evaluated in one of the experiments. The other experiment was set to evaluate green ear and dry grain yield. The inbreds BQPM-4 and BAU1M-4 were found to be the most productive with respect to the weight of marketable husked and unhusked baby corn ears. The inbreds BAU1M-4 and BQPM-2 were the most productive with respect to number and weight of marketable husked green ears and grain yield. Therefore, the cultivars differ with each other when different corn exploiting purposes are taken into account.

Keywords
Baby corn; Green ear; Yield; Zea mays L.

Maize is the third most important cereal crop in India after rice and wheat. Due to the change in food pattern and shift in cropping system, maize is gaining its importance as baby corn, green ear, dry grain, popcorn, etc for human consumption. Hence, diversified uses of maize have led to its ever increasing demand. Cultivation of maize for green ear and grain production are the common practices in India. Immature ears harvested in 25 to 28 days after pollination with moisture content of 70 to 80% is called green ear corn.
The unfertilized tender ear harvested two or three days after silk emergence is called baby corn. Baby corn (Zea mays L.) is a diversified product composed of baby or young ears harvested before fertilization and consumed as a fresh or canned vegetable (Kumar and Kallo, 2000). It is rich in vitamins B and C, potassium, fibres and carotenoids. After harvesting of baby corn or green ear, the above ground parts (stubbles) can be used as animal fodder. Baby corn is a profitable crop that allows diversification of production, aggregation of value and increased income (Pandey et al., 2002).
Most maize cultivars have been developed for grain production. Sweet corn cultivar may be used for green ear as well as grain production and any corn cultivar with higher prolificacy and better tolerance to high plant density can be used for baby corn cultivation. As a product, baby corn was only important in Thailand and a few other countries (Pereira Filho et al., 1998). Because of globalization, other countries have become interested in this crop. In addition to supplying the growing domestic demand, this product could be included in the export list of agricultural companies, taking advantage of the existing export chain used for fruits, ornamental plants, and other products. Considering the diversified uses of maize, interest has been demonstrated for the evaluation of maize hybrids with regard to their baby corn, green ear and grain yield production ability.
1 Materials and Methods
Seventeen inbred lines were evaluated for baby corn, green ear and grain yield in two different experiments. They were evaluated for baby corn in one of the experiment and for green ear traits and grain yield in another experiment in the neighbouring plots in the same season and were managed in a similar way in RBD (Randomized Block Design) with three replicates in kharif 2010 and rabi 2011-12. Each plot consisted of two rows of 2.5 m length but 65 cm apart, i.e. plot size was 3.25 m2 for baby corn trial while it was 2.5 m long and 70 cm apart, i.e. plot size was 3.5 m2 for green ear traits and grain yield trial. All other recommended agronomical practices were followed.
1.1 Experiment 1: Baby corn yield and other traits
The evaluated traits were weight of husked and unhusked ears, length and diameter of husked and unhusked ears, fresh tassel weight, plant height, ear insertion height and fresh weight of above ground part of the plant. The total weights of ears were estimated based on the total number of ears harvested from the usable area of the plot. Unhusked ears, free of damage caused by pests or diseases were considered marketable. Husked ears that presented good health, a color varying from pearly white to light yellow, cylindrical shape with a diameter ranging from 0.8 to 1.8 cm and length ranging from 4 to 12 cm were considered marketable. Marketable ear diameter and length were evaluated using a caliper rule. The fresh weight of above-ground part was estimated based on 10 ears, five crushed plants, the crushed roots of two plants, and ten tassels, respectively. Plant height (distance from the soil level to the insertion point of the highest leaf) and ear insertion height (distance from the soil level to the ear insertion node), and tassel characteristics were evaluated in the same ten plants selected at random from the usable area of each plot.
1.2 Experiment 2: Green ear yield, grain yield and other traits
This experiment was planted on the same date, in a neighboring area, and managed in a similar way. The usable area was considered as the space occupied by the two central rows, with the elimination of plants from one pit at each end. One of the usable rows was chosen at random for green ear yield assessment, and the other was used for grain yield assessment.
The evaluated traits were total number and weight of green ears per plant, plant height, ear insertion height and grain yield and its components. The total number and mass of ears were estimated based on the total number of ears harvested from the usable area of the plot. Plant height and ear insertion height were measured after dry ear harvesting. Dry corn was harvested when grain moisture content was close to 20%. Measurements were done for number of ears ha-1 (based on ears harvested from the usable area of the plot), number of kernels per ear (obtained from 15 randomly selected ears), grain yield (corrected for a 15.5% moisture content, wet basis), and 100-kernel weight (estimated based on five 100-kernel samples).
2 Results and Discussion
2.1 Experiment 1: Baby corn yield and other traits
The baby corn was harvested from 48 to 62 days after sowing, in five operations. The inbred BQPM-2 showed the greatest plant height and ear insertion height followed by BAUIM-2 (Table 1). High plant densities may cause lodging in some cultivars, in certain environments (Bavec Bavec, 2002), especially with increasing planting density it causes plant height and ear insertion height to increase as well (Modarres et al., 1998). Since baby corn is generally produced under high planting densities, preference should be given to smaller-sized cultivars, in order to decrease yield losses, which might happen if lodging occurs before flowering. The greatest fresh weight of above ground part of the plant was shown by HKI-163 followed by CM152 and BAUIM-3.
The inbred V341 showed the smallest fresh tassel weight. The tassel functions as a strong sink organ, and may demand an expressive amount of photoassimilates (Chinwuba et al., 1961). In addition, large tassels cause leaf shading (Hunter et al., 1969). Further there exist a negative correlation between tassel size and prolificacy (Souza Junior et al., 1985), which is a very important trait in cultivars intended for baby corn production. Thus, cultivars with smaller tassels seem to be important for both baby corn and grain production. Further detasseling provides an increase in the productivity of commercial baby corn ears, regardless of sowing season (Carvalho et al., 2002). Espinosa Calderon et al. (1999) studied the effects of detasselling on the performance of nineteen tropical maize lines. Overall, the baby corn yield of detasselled inbred lines was significantly higher by 30.3% than that of non-detasselled lines.
The inbred BQPM-4 followed by BAU1M-4 was found to be the most productive with respect to the weight of husked and unhusked ears (Table 2). Depending on the criterion used for yield assessment in baby corn cultivars can be different. Marketable husked ear weight is considered the most important trait for baby corn production. Besides, according to the evaluation criteria adopted for baby corn yield determination, cultivars may respond differently (Almeida et al., 2005). Tiwari and Verma (1999) evaluated that baby corn yield was positively correlated with the traits like cob yield with husk, ear diameter and fodder yield.

 

Table 1 Mean performance of parents for fresh tassel weight, plant eight, ear insertion height and fresh weight of above ground part of the plant


 

Table 2 Means performance of parents for weight of total ears per plant husked and unhusked


The inbred CML161showed the largest mean ear length for both husked and unhusked baby corn ears while the inbred BQPM-2 showed the largest mean diameter for both husked and unhusked baby corn ears (Table 3).
The moisture content for baby corn ears varied from 85% (inbred HKI 193-1) to 90% (inbred BQPM-4). However other researchers obtained a mean value of 89% (Yodpet, 1979) or variation of 90% to 95% (Carvalho, 2002).

 

Table 3 Means performance of parents for diameter and length of unhusked and husked marketable ears


2.2 Experiment 2: Green ear yield, grain yield and other traits
The green ears were harvested from 65 to 78 days after planting date, in three harvesting operations. The inbred BAU1M-4 recorded the maximum number and weight of green ears per plant followed by BQPM-2 (Table 4). Differences between cultivars with regard to traits for green corn yield evaluation were also observed by other authors (Silva et al., 1997 and Silva et al., 1998).
The inbred V341 showed the smallest plant height while the inbred CM152 showed the smallest ear height. The maximum number of kernels per ear was shown by BQPM-2 followed by BAUIM-4. However, the greatest mass of 1000 grains as well as grain yield per plant at 15% moisture was shown by BAU1M-4 followed by BQPM-2. The fact that cultivars differed with respect to green ear yield but showed the same grain yield could be due to several factors like at the time when green ears are harvested, grain filling is obviously not complete and cultivars may differ with regard to their grain filling rate and duration of the grain filling period (Poneleit and Egli, 1979).
The inbreds BQPM-4 and BAU1M-4 were found to be the most productive with respect to the weight of husked and unhusked baby corn ears. The inbreds BAU1M-4 and BQPM-2 were the most productive with respect to number and weight of marketable husked green ears and grain yield. Therefore, the cultivars differ with each other when different corn exploiting purposes are taken into account (Itala Paula et al., 2003).

 

Table 4 Mean performance of Parents for No. and weight of green ears/plant, pant height, ear height, No. of kernels/ear, 1000 dry grain weight and grain yield/plant at 15%moisture


Acknowledgement
The work has been carried out in Ph.D. programme under the financial support of Department of Science and Technology, Govt. of India for professional fellowship through INSPIRE programme.
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