시료 준비 방법에 따른 등숙 시기별 초당 및 찰옥수수 교잡종의 과피 두께 비교

Comparison of Kernel Sample Preparation Methods at Different Grain Filling Periods for Determining Pericarp Thickness in Super Sweet and Waxy Corn Hybrids

Abstract

본 연구는 식용옥수수 풋이삭의 식감의 결정에 영향을 미치는 과피의 두께를 측정하는 방법을 규명하기 위하여 과피 시료의 준비 방법에 따른 과피 두께의 차이와 등숙 시기별 과피 두께의 변화를 조사하기 위하여 수행하였다. 1. 찰옥수수와 초당옥수수 각 3품종의 시료를 수확 직후 생옥수수(생시료) 알곡을 바로 측정하거나 상온의 음지에서 완전(건조시료) 건조시키거나 $-4^{\circ}C$로 냉동시킨 후 과피를 측정하였다. 2. 시료 준비 방법과 등숙 시기에 따른 삼원 교호작용의 유의성이 인정되어 어느 한 요인에 대한 일반적인 결론을 도출하기 보다는 각 시료 준비 방법과 특정 등숙 시기에 따른 과피 두께의 비교를 수행하였다. 3. 초당옥수수는 건조시료에서 등숙이 진행됨에 따라 비교적 안정된 과피 두께 측정값을 얻을 수 있었으며 찰옥수수는 비해 모든 시료 준비 방법에서 초당옥수수보다 안정된 값을 보였다. 특히 풋찰옥수수 수확 적기인 수정 후 24일경에는 시료 준비 방법에 따른 차이는 크게 나타나지 않을 것으로 기대된다.

Pericarp thickness of vegetable corns such as sweet and waxy corn is one of the crucial traits, contributing to their edible quality. This study was carried out to compare the pericarp thickness of super sweet and waxy corn hybrids measured with kernel samples prepared using different methods at different grain filling periods. The samples comprised excised pericarp from dried, frozen (at $-4^{\circ}C$), and fresh kernels. Analysis of variance performed separately on super sweet and waxy corn hybrids indicated a significant three-way interaction among cultivars, kernel sample preparation methods, and days after pollination (DAP). Dried samples of super sweet corn hybrids presented reasonably stable pericarp thickness measurements during grain filling, while all the sample preparation methods fluctuated less as grains of waxy corn hybrids matured. Waxy corn is best consumed at around 24 days after pollination. Pericarp thickness of waxy kernel samples regardless of preparation methods investigated was the same at 24 DAP with a few exceptions. Overall, the common method of drying kernel samples before pericarp excision can provide reliable data for estimating the tenderness of vegetable corn hybrids.

Fig. 1. Changes in pericarp thickness of super sweet corn hybrids during grain filling. The thickness was measured for kernel samples prepared by three different methods: fresh (△), dried (○), and frozen (□) immediately after harvest. The graphs are arranged by a) cultivar and b) method. The error bar indicates ± standard error of the mean (n = 3) calculated from the mean square of error.

Fig. 2. Changes in pericarp thickness of waxy corn hybrids during grain filling. The thickness was measured for kernel samples prepared by three different methods: fresh (△), dried (○), and frozen (□) immediately after harvest. The graphs are arranged by a) cultivar and b) method. The error bar indicates ± standard error of the mean (n = 3) calculated from the mean square of error.

Table 1. Analysis of variance for pericarp thickness of super sweet corn hybrids.

Table 2. Analysis of variance for pericarp thickness of waxy corn hybrids.

Table 3. Average and standard deviation of pericarp thickness (μm) of super sweet corn hybrids.

Table 4. Average and standard deviation for pericarp thickness (μm) of waxy corn hybrids