(i) Triticale (Hexaploid) (6x) is the first man made cereal.
(ii) It is obtained from a cross between tetraploid wheat Triticum durum and rye (diploid).

(iii) Triticale hybrid plants, have characteristics of both macroni wheat and rye.
(iv) They combine the high-protein content of wheat a high content of amino acid lysine of rye.

  
types of aneuploidy.

The diagrammatic representation of position of genes and related distances between the adjacent genes is called gene mapping. 
Uses 
(i) Used to determine gene order.
(i) Identify the locus of a gene.
(i) Calculate the distance between genes.
(i) Useful in predicting results of dihybrid and trihybrid crosses.
(i) Allows the geneticists to understand the overall genetic complexity of particular organism.

Zea mays is a monoecious plant with
(i) Male inflorescence - the tassel with staminateflowers
(ii) Female inflorescence - ear or cob with pistillate flowers. 
(iii) Unisexuality in maize is through selective abortion of stamens - in ear florets and Pistils - in tassel florets. 
(iv) A substitution of two single gene pairs 'ba' for barren plant and 'ts' - for tassel seed makes the differences between monoecious and dioecious (rare) maize plants. 
(v) The allele for barren plant (ba) when homozygous makes the stalk staminate by eliminating silk and ears. 
(vi) The allele for tassel seed (ts) transforms tassel into a pistillate flower. 
(vii) The development of both inflorescence is the result of selective abortion of pistils or stamens. 

(i) Multiple alleles are reported in Nicotiana which are responsible for self, incompatibility.
(ii) The gene for self-compatibility can be designated as S, which has allelic series S₁, S₂, S₃, S₄ and S₅.
(iii) The cross-fertilizing tobacco plants were not homozygous as S₁S₁ or S₂S₂.
(iv) But, were heterozygous as S₁S₂, S₃S₄, S₅S₆.
(v) When crosses were made between different S₁S₂ plants, pollen tube did not develop normally.
(vi) But effective pollen tube developed when crossing was made with other than S₁S₂.
(vii) When crosses were made between S₁S₂ (seed parents) S₂S₃ (pollen parents), two kinds of pollen tubes were distinguished.
(viii) Pollen grains carrying S₂ were not effective.
(ix) Pollen grains carrying S₃ were capable of fertilization.
(x) In a cross between S₁S₂ X S₃S₄, all the pollens were effective.
(xi) So four kinds of progeny resulted. S₁S₃/S₁S₄/S₂S₃/S₂S_4.